CA 02550897 1997-12-11
DE1~LANI~ES OU JBRE'~ETS 'VOLU~I~NEUX
LA PRESENTE PARTIE DE CETTE DElYLaNDE OU CE BREVETS
COyIPREND PLUS D'UN TOIYIE.
CECI EST LE TOIYIE DE
NOTE: Pour les tomes additionels, veillez contacter 1e Bureau Canadien des
Brevets.
JUMBO APPLICATIONS / PATENTS
THIS SECTION OF THE APPLICATION / PATENT CONTAINS lYIOiRE
THAN ONE VOLUME.
THIS IS VOLUtI~.E ~ OF
NOTE: For additional volumes please contact the Canadian Patent Office.
CA 02550897 1997-12-11
1
PROCESSES FOR PREPARATION OF 9,11-EPORY
STEROIDS AND INTERMEDIATES USEFUL THEREIN
Backcrround of the Invention
This invention relates to the novel processes for
the preparation of 9,11-epoxy steroid compounds,
- especially those of the 20-spiroxane series and their
analogs, novel intermediates useful in the preparation of
steroid compounds, and processes for the preparation of
such novel intermediates. Most particularly, the
invention is directed to novel and advantageous methods
for the preparation of methyl hydrogen 9,lla-epoxy-17a-
hydroxy-3-oxopregn-4-ene-7x,21-dicarboxylate, y-lactone
(also referred to as eplerenone or epoxymexrenone).
Methods for the preparation of 20-spiroxane series
compounds are described in U.S. patent 4,559,332. The
compounds produced in accordance with the process of the
'332 patent have an open oxygen containing ring E of the
general formula:
Y2
1
H3C Y \\\\C CH2~ 2 C-x
v
/
A CH3Wv0 /B
i ~B
O / / i~~~ R ~
IA
in which
-A-A- represents the group -CHZ-CHI- or -CH=CH-;
R1 represents an a-oriented lower alkoxycarbonyl or
hydroxycarbonyl radical;
-B-B- represents the group -CHZ-CHZ- or an a- or (3-
oriented group;
Re R~
CH CH
-CH-CH2-CH- III
R6 and R' being hydrogen;
i
CA 02550897 1997-12-11
2
X represents two hydrogen atoms or oxo;
Yl and Yz together represent the oxygen bridge -O-,
or
Y1 represents hydroxy, and
YZ represents hydroxy, lower alkoxy or, if X
represents H2, also lower alkanoyloxy;
and salts of such compounds in which X represents
oxo and Y2 represents hydroxy, that is to say of
corresponding 17~i-hydroxy-21-carboxylic acids.
U.S. patent 4,559,332 describes a number of methods
for the preparation of epoxymexrenone and related
compounds of Formula IA. The advent of new and expanded
clinical uses for epoxymexrenone create a need for
improved processes for the manufacture of this and other
related steroids.
Summary of the Invention
The primary object of the present invention is the
provision of improved processes for the preparation of
epoxymexrenone, other 20-spiroxanes and other steroids
having common structural features. Among the particular
objects of the invention are: to provide an improved
process that produces products of Formula IA and other
related compounds in high yield; the provision of such a
process which involves a minimum of isolation steps; and
the provision of such a process which may be implemented
with reasonable capital expense and operated at
reasonable conversion cost.
Accordingly, the present invention is directed to a
series of synthesis schemes for epoxymexrenone;
intermediates useful in the manufacture of
epoxymexrenone; and syntheses for such novel
intermediates.
The novel synthesis schemes are described in detail
in the Description of Preferred Embodiments. Among the
CA 02550897 1997-12-11
3
novel intermediates of this invention are those described
immediately below.
A compound of Formula IV corresponds to the
structure:
Re
2 R9
R _
~8
B
/ ~i,~ t
o R IV
wherein:
-A-A- represents the group -CHR°-CHRs- or
_CRa=CRs_
R3, R' and Rs are independently selected from the
group consisting of hydrogen, halo, hydroxy, lower
alkyl, lower alkoxy, hydroxyalkyl, alkoxyalkyl,
hydroxy carbonyl, cyano and aryloxy;
R1 represents an alpha-oriented lower alkoxycarbonyl
or hydroxycarbonyl radical;
R2 is an lla-leaving group the abstraction of which
is effective for generating a double bond between
the 9- and 11- carbon atoms;
-B-B- represents the group -CHR6-CHR'- or an alpha-
or beta- oriented group:
Re R~
\ ~
CH CH
2O -cH-CHZ-cH- III
where R6 and R' are independently selected from the
group consisting of hydrogen, halo, lower alkoxy,
CA 02550897 1997-12-11
4
acyl, hydroxalkyl, alkoxyalkyl, hydroxycarbonyl,
alkyl, alkoxycarbonyl, acyloxyalkyl, cyano and
aryloxy; and .
Re and R' are independently selected from the group
consisting of hydrogen, hydroxy, halo, lower alkoxy,
acyl, hydroxyalkyl, alkoxyalkyl, hydroxycarbonyl,
alkyl, alkoxycarbonyl, acyloxyalkyl, cyano and
aryloxy, or Ra and R' together comprise a carbocyclic
or heterocyclic ring structure, or Re or R' together
with R6 or R' comprise a carbocyclic or heterocyclic
ring structure fused to the pentacyclic D ring.
A compound of Formula IVA corresponds to Formula IV
wherein Re and R' together with the.ring carbon to which
they are attached form the structure:
Y2
Y j~~~ ~) hiii( cHp) s - ~ ' x XXXIV
where X, Yl, YZ and C ( 17 ) are as defined above .
A compound of Formula IVB corresponds to Formula IV
wherein RB and R9 together form the structure of Formula
XXXIII:
0
0
,mn XXXIII
Compounds of Formulae IVC, IVD and IVE,
respectively, correspond to any of Formula IV, IVA, or
IVB wherein each of -A-A- and -H-H- is -CH2-CHz-, R3 is
hydrogen, and R1 is alkoxycarbonyl, preferably
methoxycarbonyl. Compounds within the scope of Formula
IV may be prepared by reacting a lower alkylsulfonylating
or acylating reagent, or a halide generating agent, with
a corresponding compound within the scope of Formula V.
CA 02550897 1997-12-11
A compound of Formula V corresponds to the
structure:
R3
ps
H 0,~~~
B
B
/ i,,~ R ~
V
wherein -A-A-, -B-H-, Rl, R3, R8 and R' are as defined in
5 Formula IV.
A compound of Formula VA corresponds to Formula V
wherein RB and R9 with the ring carbon to which they are
attached together form the structure:
Y=
Y~
/C\1 7) hiii( CNp) 2 - C ' X
XXXIV
where X, Y1, Y~ and C(17) are as defined above.
A compound of Formula VB corresponds to Formula V
wherein RB and R9 together form the structure of Formula
XXXIII:
XXXIII
Compounds of Formulae VC, VD and VE, respectively,
correspond to any of Formula V, VA, or VH wherein each of
-A-A- and -B-B- is -CH2-CHZ-, R3 is hydrogen, and Rl is
alkoxycarbonyl, preferably methoxycarbonyl. Compounds
within the scope of Formula V may be prepared by reacting
an alkali metal alkoxide with a corresponding compound of
Formula VI.
A compound of Formula VI corresponds to the
structure
0
CA 02550897 1997-12-11
6
R3 R8
R9
H 0,~~~
8
I ~CN
VI
wherein -A-A-, -B-H-, R3, Re and R9 are as defined in
Formula IV.
A compound of Formula VIA corresponds to Formula VI
wherein Re and R9 together with the ring carbon to which
they are attached form the structure:
Y=
Y ~~
/C\1 7) VIII( CHz) z - C ~ X
xxxlv
where X, Y1, Y~ and C(17) are as defined above.
A compound of Formula VIB corresponds to Formula VI
wherein RB and R9 together form the structure of Formula
XXXIII:
XXXIII
Compounds of Formulae VIC, VID and VIE,
respectively, correspond to any of Formula VL, VIA, or
VIB wherein each of -A-A- and -E-B- is -CHZ-CH2-, and R3
is hydrogen. Compounds of Formula VI, VIA, VIB and VIC
are prepared by hydrolyzing a compound corresponding to
Formula VII, VIIA, VIIB or VIIC, respectively.
A compound of Formula VII corresponds to the
structure:
0
,11111
CA 02550897 1997-12-11
7
R3 Re
I v R9
.,AJ~~e 8
NHZ VII
wherein -A-A- , -B-B- , R' , R8 and R9 are as def fined in
Formula IV.
A compound of Formula VIIA corresponds to Formula
VII wherein Re and R9 together with the ring carbon to
vuhich they are attached form the structure:
Yz
Y~
~C( 1 7) hiii( CNp) 2 - C - X
XXXIV
where X, Y1, YZ and C ( 17 ) are as def fined above .
A compound of Formula VIIB corresponds to Formula
VII wherein Re and R9 together form the structure of
Formula XXXIII:
XXXIII
Compounds of Formulae VIIC, VIID and VIIE,
respectively, correspond to any of Formula VII, VIIA, or
VIIB wherein each of -A-A- and -B-B- is -CHz-CHz-, and R'
is hydrogen. A compound within the scope of Formula. VII
may be prepared by cyanidation of a compound within the
scope of Formula VIII.
A compound of Formula VIII corresponds to the
structure:
0
CA 02550897 1997-12-11
8
R3 R8
Rs
H 0,~~~
B
/ /
~ VIII
wherein -A-A- , -B-B- , R3 , R8 and R' are as def fined in
Formula IV.
A compound of Formula VIIIA corresponds to Formula
VIII wherein R8 and R9 together with the ring carbon to
which they are attached form the structure:
Y2
Y ~C( 1 7) mn( CHp) p - C . X XXXIV
/ \
where X, Y1, YZ and C(17) are as defined above.
A compound of Formula VIIIB corresponds to Formula
VIII wherein R8 and R9 together form the structure of
Formula XXXIII:
XXXIII
Compounds of Formulae VIIIC, VIIID and VIIIE,
respectively, correspond to any of Formula VIII, VLIIA,
or VIIIB wherein each of -A-A- and -H-B- is -CH2-CH2-, and
R3 is hydrogen. Compounds within the scope of Formula
VIII are prepared by oxidizing a substrate comprising a
compound of Formula XXX as described hereinbelow by
fermentation effective for introducing an 11-hydroxy
group into the substrate in a-orientation.
A compound of Formula IX corresponds to the
structure:
0
CA 02550897 1997-12-11
9
R3 Re
I ~ R9
''OOH 'B
A
Ai 8
0/ / ..yR1
IX
where -A-A-, -B-B-, R', Re and R9 are as defined in
Formula IV, and R1 is as defined in Formula V.
A compound of Formula IXA corresponds to Formula TX
wherein Ra and R9 together with the ring carbon to which
they are attached form the structure:
Y$
t
Y~C~1 7) mn( CHp) Z - C ' !x XXXIV
where X, Y1, Y2 and C ( 17 ) are as def fined above .
A compound of Fornnula IXB corresponds to Formula IX
wherein Re and R9 together with the ring carbon to which
they are attached form the structure of Formula XXXIII:
0
XXXIII
Compounds of Formulae IXC, IXD and IXE,
respectively, correspond to any of Formula IX, IXA, or
IXB wherein each of -A-A- and -B-B- is -CHz-CH2-, and R3
is hydrogen. Compounds within the scope of Formula IX
can be prepared by bioconversion of a corresponding
compound within the scope of Formula X.
A compound of Formula XIV corresponds to the
structure:
0
CA 02550897 1997-12-11
1~
R~ Rt
~Ha~ ~ _Rs
A,A B
CN
O
fl
XIV
wherein -A-A-, -B-B-, R', Re and R9 are as defined in
Formula IV.
A compound of Formula XIVA corresponds to Formula
XIV wherein~RB and R9 together with the ring carbon to
which they are attached form the structure:
Y2
Y~
/C\1 7) iiii~( CH=) y ~ C - X
XXXIV
where X, Y1, Yz and C ( 17 ) are as def fined above .
A compound of Formula XIVB corresponds to Formula
XIV wherein RB and R9 together with the ring carbon to
which they are attached form the structure of Formula
XXXIII:
XXXIII
Compounds of Formulae XIVC, XIVD and XIVH,
respectively, correspond to any of Formula XIV, XIVA, or
XIVB wherein each of -A-A- and -B-H- is -CHZ-CH2-, and R3
is hydrogen. Compounds within the scope of Formula XIV
can be prepared by hydrolysis of a corresponding compound
within the scope of Formula XV.
A compound of Formula XV corresponds to the
structure:
0
CA 02550897 1997-12-11
11
R9 a
H3C R Re
CHs I ~B
A/A B
CN
,
C
NH2 XV
wherein -A-A- , -B-B- , R3 , R8 and R9 are as def fined in
Formula IV.
A compound of Formula XVA corresponds to Formula XV
wherein R8 and R9 together with the ring carbon to which
they are attached form the structure:
Y2
Y~C\17) mn( CHZ) 2 - C - X
XXXIV
where X, Y1, YZ and C ( 17 ) are as defined above .
A compound of Formula XVB corresponds to Formula XV
l0 wherein RB and R9 together with the ring carbon to which
they are attached form the structure of Formula XXXIII:
XXXIII
Compounds of Formulae XVC, XVD and XVE,
respectively, correspond to any of Formula XV, XVA, or
XVB wherein each of -A-A- and -B-H- is -CHZ-CH2-, and R3
is hydrogen. Compounds within the scope of Formula XV
can be prepared by cyanidation of a corresponding
compound within the scope of Formula XVI.
A compound of Formula XXI corresponds to the
structure:
0
I
CA 02550897 1997-12-11
12
H3C
p
I ( R R9
CH I''~p B
AiA 8
I _CN
fl
o XXI
wherein -A-A-, -B-B-, R', R8 and R9 are as defined in
Formula IV.
A compound of Formula XXIA corresponds to Formula
XXI wherein RB and R9 together with the ring carbon to
which they are attached form the structure:
Y2
Y~
~C\1 7) VIII( CH2) p ~ C ~ X HIV
where X, Yl, YZ and C ( I7 ) are as def fined above .
A compound of Formula XXIH corresponds to Formula
XXI wherein R8 and R9 together form the structure of
Formula XXXIII:
III XXXIII
Compounds of Formulae XXIC, XXID and XXIE,
respectively, correspond to any of Formula XXI, XXIA, or
XXIB wherein each of -A-A- and -B-B- is -CH2-CH2-, and R'
is hydrogen. Compounds within the scope of Formula XXI
may be prepared by hydrolyzing a.corresponding compound
within the scope of Formula XXII.
A compound of Formula XXII corresponds to the
structure:
0
II
CA 02550897 1997-12-11
13
H3C
R3 Re
\ R9
CH3.~i0 B
w
AiA B
CN
0
C
N z XXII
wherein -A-A-, -B-B-, R3, Re and R9 are as defined in
Formula IV.
A compound of Formula XXIIA corresponds to Formula
XXII wherein R8 and R9 together with the ring carbon to
which they are attached form the structure:
Y~
Y y
/C\1 7) hiii( Chl2) 2 - C - X
XXXIV
where X, Y1, Y2 and C(17) are as defined above.
A compound of Formula XXIIB corresponds to Formula
XXII wherein R8 and R9 together form the structure of
Formula XXXIII:
XXXIII
Compounds of Formulae XXIIC, XXIID and XXIIE,
respectively, correspond to any of Formula XXII, XXIIA,
or XXIIB wherein each of -A-A- and -H-H- is -CH2-CHZ-, and
R' is hydrogen. Compounds within the scope of Formula
XXII may be prepared by cyanidation of a compound within
the scope of Formula XXIII.
A compound of Formula XXIII corresponds to the
structure:
0
CA 02550897 1997-12-11
14
H3C
R3 Re ;;
R9
CH3~\w 'B
A/A v 8
/ /
XXIII .
wherein -A-A-, -B-B-, R3, R8 and R9 are as defined in
Formula IV.
A compound of Formula XXIIIA corresponds to Formula
XXIII wherein R8 and R9 together with the ring carbon to
which they are attached form the structure:
Yq
t
Y ~C( 1 ~) um(.CHpj x - C ' X
/ \ XXXIV
where X, Yl, Y~ and C ( 17 ) are as defined above .
A compound of Formula XXIIIH corresponds to Formula
XXIII wherein R8 and R9 together form the structure of
Formula XXXIII:
XXXIII
Compounds of Formulae XXIIIC, XXIIID and XXIIIE,
respectively, correspond to any of Formula XXIII, XXIIIA,
or XXIIIB wherein each of -A-A- and -B-B- is -CH2-CH2-,
and R' is hydrogen. Compounds within the scope of Formula
XXIII can be prepared by oxidation of a compound of
Formula XXIV, as described hereinbelow.
A compound of Formula XXVI corresponds to the
structure:
0
0
CA 02550897 1997-12-11
0
H3C
R3 0
hiii
CH3 '8
A/A B
OR"
~ ~ ,J
~i
wherein -A-A-, -H-B-, R3, R8 and R9 are as defined in
Formula IV.
A compound of Formula XXVIA corresponds to Formula
5 XXVI wherein each of -A-A- and -B-H- is -CHZ-CH2-, and R3
is hydrogen. Compounds within the scope of Formula XXVI
can be prepared by oxidation of a compound of Formula
XXVII.
A compound of Formula XXV corresponding to the
10 structure:
0
H3C
R3 0
iiii
r \
CH3 ~~OR" 8
/
AiA B
CN
0 ~ ;%
C
N H 2 XXV
wherein -A-A-, -B-B-, R3, R8 and R9 are as defined in
Formula IV.
A compound of Formula XXVA corresponds to Formula
15 XXV wherein each of -A-A- and -B-H- is -CH2-CH2- , and R3
is hydrogen. Compounds within the scope of Formula XXV
can be prepared by cyanidation of a compound of Formula
XXVI.
A compound of Formula 104 corresponds to the
structure:
CA 02550897 1997-12-11
16
0
RS
O
HO,~~~ __
g
A,A
R~~O \ \
104
wherein -A-A-, -B-B- and R3 are as defined in Formula IV,
and R11 is C1 to C, alkyl.
A compound of Formula 104A corresponds to Formula
104 wherein each of -A-A- and -B-B- is -CH2-CH2-, and R3
is hydrogen. Compounds within the scope of Formula 104
may be prepared by thermal decomposition of a compound of
Formula 103.
A compound of Formula 103 corresponds to the
structure:
0
qa O ~O2R~:
g
i
B
p ~ ~ p~ ~/' ~/
103
wherein -A-A-, -B-B-, R' and R11 are as defined in Formula
104, and R12 is a Cl to C, alkyl.
A compound of Formula 103A corresponds to Formula
103 wherein each of -A-A- and -B-H- is -CFI2-CH2-, and R3
is hydrogen. Compounds within the scope of Formula 103
may be prepared by reaction of a corresponding compound
of Formula 102 with a dialkyl malonate in the presence of
a base such as an alkali metal alkoxide.
A compound of Formula 102 corresponds to the
structure:
CA 02550897 1997-12-11
17
Rs
O~
H 0,~~~
B
AiA B
R~~O
102
wherein -A-A-, -B-B-, R3 and R11 are as defined in Formula
104.
A compound of Formula 102A corresponds to Formula
102 wherein each of -A-A- and -B-H- is -CHz-CHZ-, and R'
is hydrogen. Compounds within the scope of Formula 102
may be prepared by reaction of a corresponding compound
of Formula 101 with a trialkyl sulfonium compound in the
presence of a base.
A compound of Formula 101 corresponds to the
structure:
R~
O
B
i
B
Rat." _ _
101
wherein -A-A-, -B-B-, R3 and R11 are as defined in Formula
104.
A compound of Formula lOlA corresponds to Formula
101 wherein each of -A-A- and -B-B- is -CHZ-CH2-, and R3
is hydrogen. Compounds within the scope of Formula 101
may be prepared by reaction of lla-hydroxyandrostene-
3,1'7-dione or other compound of Formula XXXVI with a
trialkyl orthoformate in the presence of an acid.
A compound of Formula XL corresponds to the Formula:
CA 02550897 1997-12-11
18
R9 Reo
Rio
~ ~B B
CN
wherein -E-E- is selected from among:
Rz~ p2z
C- C-
xLizl
R21
= C- xLIV
A21 OR24
\C C-
S XLV
OR2~ R2'
\~ ~
C C-
R22
XLVI
and
0
jC=CRZ~ -
XLVII
CA 02550897 1997-12-11
19
R21, Rz2 and Rz3 are independently selected from among
hydrogen, alkyl, halo, nitro, and cyano; R~' is selected
from among hydrogen and lower alkyl; R8° and R'° are
independently selected from keto and the substituents
that may constitute Re and R9 (as defined hereinabove with
reference to Formula IV); and -A-A-, -H-B- and R' are as
defined in Formula IV.
A compound of Formula XLA corresponds to Formula XL
wherein R21, Rz2 and RZ' are independently selected from
l0 among hydrogen, halogen and lower alkyl.
A compound of Formula XLB corresponds to Formula XLA
wherein -E-E- corresponds to Formula XLIII, XLIV, XLV or
XLVII. A compound of Formula XLC corresponds to Formula
XLB wherein -E-E- corresponds to Formula XLV. A compound
of XLD corresponds to Formula XLB wherein -E-E-
corresponds to Formula XLVII.
A compound of Formula XLE corresponds to Formula XL
wherein Re° and R9° together with the ring carbon atom to
which they are attached comprise keto or:
Yp
YjC\17) mn( CHZ) 2 - I ' X XXXIV
where X, Y1, Yz and C (17) are as deffined above, or
0
0
XXXIII
Compounds of Formula XLIE correspond to Formula XL
in which Re° and R9° together form keto.
Compounds of Formulae XLF, XLG, XLH, XLJ, XLM, and
XLN correspond to Formula XL, XLA, XLB, XLC, XLD and XLE,
respectively, in which -A-A-, -B-B- and R3 are as defined
above.
CA 02550897 1997-12-11
A compound of Formula XLI corresponds to the
Formula:
R9 i0
R Rao
E \
I s
AAA E
R~ e0
_ _ (soa
p~i0 p~ sch~ms 9)
\\O
xLl XLI
wherein -E-E- is selected from among:
RZ~ R22
C- C-
R23 XLIII
5
R2~ OR24
\ C C-
XLV
ORT~ R21
C C-
R22
XLVI
and
0
~c-cR2' - XLVII
10 R18 is C1 to C, alkyl or the RleO- groups together form an
O, O-oxyalkylene bridge; R21, R~~ and R2' are independently
selected from among hydrogen, alkyl, halo, vitro, and
cyano; R2' is selected from among hydrogen and lower
alkyl; R°° and R9° are independently selected from keto
and
15 the substituents that may constitute Re and R9; and -A-A-,
-B-B- and R3 are as defined in Formula IV.
CA 02550897 1997-12-11
21
A compound of Formula XLIA corresponds to Formula
XLI wherein R~1, R~2 and Rz3 are independently selected from
among hydrogen, halogen, and lower alkyl.
A compound of Formula XLIB corresponds to Formula
XLIA wherein -E-E- corresponds to Formula XLIII, XLIV,
XLV or XLVII.
A compound of Formula XLIC corresponds to Formula
XLI wherein Re° and R9° together with the ring carbon atom
to which they are attached comprise keto or:
Y2
Y'~C( 1 7) W n( CH2) Z . C . X
~ ~ XXXIV
where X, Yl, Y2 and C ( 17 ) are as defined above .
Compounds of Formulae XLID correspond to Formula XLI
in which the substituent XXXIV corresponds to the
structure XXXIII
0
0
,mn XXXIII
Compounds of Formula XLIE correspond to Formula XL
in which R8° and R9° together form keto.
. Compounds of Formulae XLIF, XLIG, XLIH, XLIJ, XLIM,
and XLIN correspond to Formula XLI, XLIA, XLIB, XLIC,
XLID and XLIE, respectively, in which -A-A-, -B-B- and R3
are as defined above. Compounds within the scope of
Formula XLI are prepared by hydrolysis of corresponding
compounds of Formula XL as defined hereinbelow.
A compound of Formula XLII corresponds to the
Formula:
CA 02550897 1997-12-11
22
Ro 10
Roo
E~ \
8
E
B
=v._
~O
XLII
wherein -E-E- is selected from among.:
A29 R22
C- C-
p23
XLIII
R2~
/C c
XLIV
p2~ ~R2~
\C C
-
2
2
XLV
~Rz~ Rzt
\I
C C-
Rz2
xLVI
and
0
~c cR~' - XLVII
Rzl, Rz2 and R" are independently selected from among
hydrogen, alkyl, halo, nitro, and cyano; R24 is selected
from among hydrogen and lower alkyl; Re° and R9° are
independently selected from keto and the substituents
that may constitute RB and R9; and -A-A-, -B-B- and R3 are
as defined in Formula IV.
CA 02550897 1997-12-11
23
A compound of Formula XLIIA corresponds t o Formula
XLII wherein R21, RZZ and R23 are independently selected
from among hydrogen, halogen and lower alkyl.
A compound of Formula XLIIB corresponds to Formula
XLIIA wherein -E-E- corresponds to Formula XLIII; XLIV,
XLV or XLVII.
f
A .compound of Formula XLIIC corresponds to Formula
XLII wherein R8° and R9° together with the ring carbon to
which they are attached comprise keto or:
YZ
Y /C~~ 7) hiii( CHI) 2 . C _ x
XXXIV
where X, Y', YZ and C(17) are as defined above.
Compounds of Formulae XLIID correspond to Formula
XLII in which the substituent XXXIV corresponds to the
structure XXXIII
0
0
,mn XXXIII
Compounds of Formula XLIIE correspond to Formula
XLII in which Re° and R9° together form keto. Compounds of
Formulae XLIIF, XLIIG, XLIIH, XLIIJ, XLIIM and XLIIN
correspond to Formulae XLII, XLIIA, XLIIB, XLIIC, XLIID
and XLIIE, respectively, in which -A-A- and -B-B- are -
CHz-CHZ and R3 is hydrogen. Compounds within the scope of
Formula XLII are prepared by deprotecting a corresponding
compound of Formula XLI.
A compound of the Formula XLIX corresponds to the
structure:
CA 02550897 1997-12-11
24
R9 Re
i v
E' \
AAA E B/
I I _CN
iiii R t
XLIX
wherein -E-E- is as defined in Formula XL, and -A-A-, -H-
B-, Rl, R', RB and R9 are as defined in Formula IV.
A compound of Formula XLIXA corresponds to Formula
XLIX wherein Re and R9 with the ring carbon to which they
are attached together form the structure:
Yq
Y'
~C( 1 7) mn( CNq) Z - C ~ X
/ \ XXXIV
where X, Yl, Y~ and C ( 17 ) are as defined above .
A compound of Formula XLIXB corresponds to Formula
XLIX wherein R8 and R9 together form the structure of
Formula XXXIII:
0
0
,iun XXXIII
Compounds of Formulae XLIXC, XLIXD, XLIXE, respectively,
correspond to any of Formula XLIX, XLIXA or XLIXH wherein
each of -A-A- and -B-B- is -CHz-CHz-, R' is hydrogen and Rl
is alkoxycarbonyl, preferably methoxycarbonyl. Compounds
within the scope of Formula XLIX may be prepared by
reacting an alcoholic or aqueous solvent with a
corresponding compound Formula VI in the presence of a
suitable base.
A compound of Formula A203 corresponds to the
structure:
CA 02550897 1997-12-11
Rs to
OR ORtB
E
B
A,A E 9
R~ a0 \ \ ~~~~CHO
[A2 0 3
wherein -E-E- is selected from among:
Q2~ R22
C- C_
R23
XLIII
R2~ ~R2n
C C-
I z 2R
XLV .
OR2~ R2t
\I ~
C!
R22
RLVI
and
0
%RZ~
XLVII
R18 is selected from among Cl to C, alkyl; R21, R22 and R~'
are independently selected from among hydrogen, alkyl,
10 halo, vitro, and cyano; R~' is selected from among
hydrogen and lower alkyl; and -A-A-, -H-B- and R3 are as
defined in Formula IV.
A compound of Formula A203A corresponds to Formula
A203 wherein R21, Rzz and RZ3 are independently selected
15 from among hydrogen, halogen, and lower alkyl.
CA 02550897 1997-12-11
26
A compound of Formula A203B corresponds to Formula
A203A wherein -E-E- corresponds to Formula XLIII, XLIV,
XLV or XLVII.
Compounds of Formulae A203C, A203D, and A203E
respectively correspond to Formula A203, A203A and A203B
wherein each of -A-A- and -B-B- is -CH2-CHz-, and R3 is
hydrogen. Compounds within the scope of Formula A203 are
prepared by reducing a compound of Formula A202 as
defined hereinbelow.
A compound of Formula A204 corresponds to the
structure:
Rs
O
E' \
B~8
Rt9
t~ ~ v - v
R O o-='
[A2 04 ]
wherein R19 is Cl to C4 alkyl , and -E-E- , -A-A- , -B-B- and
R' are as defined in Formula 203.
A compound of Formula A204A corresponds to Formula
A204 wherein R21, R22 and R23 are independently selected
from among hydrogen, halogen, and lower alkyl.
A compound of Formula A204H corresponds to Formula
A2o4A wherein -E-E- corresponds to Formula XLIII, XLIV,
XLV or XLVII.
Compounds of Formulae A204C, A204D, and A204E
respectively correspond to Formulae A204, A204A, and
A204B wherein each of -A-A- and -B-H- is -CH2-CHI-, and R3
is hydrogen. Compounds within the scope of Formula A204
are prepared by hydrolysis of corresponding compounds of
Formula A203.
A compound of Formula A205 corresponds to the
structure:
... , .. . I
CA 02550897 1997-12-11
27
R3 n
B
R~°
R " O O
~oR2° [A205]
wherein RZ° is Cl to C, alkyl, and -E-E-, Ri9, -A-A-, -B-B-
and R3 are as defined in Formula 204.
A compound of Formula A205A corresponds to Formula
A205 wherein RZ', R22 and R2' are independently selected
from among hydrogen, halogen, and lower alkyl.
A compound of Formula A205B corresponds to Formula
A205A wherein -E-E- corresponds to Formula XLIII, XLIV,
XLV or XLVII.
Compounds of Formulae A205C, A205D and A205E
respectively correspond to Formula A205, A205A and A205B
wherein each of -A-A- and -B-B- is -CHZ-CHZ-, and R' is
hydrogen. Compounds within the scope of Formula A205 may
be prepared by reacting a corresponding compound of
Formula A204 with an alkanol and acid.
A compound of Formula A206 corresponds to the
structure:
R3
n
B
R~~
R"O O~
\OR2o
[A206]
wherein R'9, RZ°, -E-E- , -A-A- , -B-B- and R3 are as def fined
in Formula 205.
A compound of Formula A206A corresponds to Formula
A206 wherein RZl, Rzz and R2' are independently selected
from among hydrogen, halogen, and lower alkyl.
CA 02550897 1997-12-11
28
A compound of Formula A206B corresponds to Formula
A206A wherein -E-E- corresponds to Formula XLIII, XLIV,
XLV or XLVII.
Compounds of Formulae A206C, A206D and A206E
respectively correspond to Formula A206, A206A, and A206B
wherein each of -A-A- and -B-B- is -CHz-CHz-, and R3 is
hydrogen. Compounds within the scope of Formula A206 may
be prepared by reacting a, corresponding compound within
the scope of Formula A205 with a trialkyl sulfonium
halide.
A compound of Formula A207 corresponds to the
structure:
0
C02R25
R~8
\0R20
[A207]
wherein Rzs is Cl to C4 alkyl, and -E-E-, R19, Rzo, _A_A-,
-H-B- and R' are as defined in Formula A205.
A compound of Formula A207A corresponds to Formula
A207 wherein Rzl, Rzz and Rz' are independently selected
from among hydrogen, halogen, and lower alkyl.
A compound of Formula A207B corresponds to Formula
A207A wherein -E-E- corresponds to Formula XLIII, XLIV,
XLV or XLVII.
Compounds of Formulae A207C, A207D and A207E
respectively correspond to Formula A207, A207A and A207B
wherein each of -A-A- and -B-H= is -CHz-CHz-, and R' is
hydrogen. Compounds of Formula A207 can be prepared by
reaction of compounds of Formula A206 with a dialkyl
malonate.
CA 02550897 1997-12-11
29
A compound of Formula A208 corresponds to the
structure
R9 veo
R9°
Rt9
R' 9 o~oR2° [A208]
wherein -E-E-, R8° and R9° are as defined in Formula XLII;
-A-A-, -B-B- and R3 are as defined in Formula 104; and
R19, RZ°, -A-A-, -B-B-, and R3 are as defined in Formula
205.
A compound of Formula A208A corresponds to Formula
A208 wherein R21 and R22 are independently selected from
among hydrogen, halogen, and lower alkyl.
A compound of Formula A208B corresponds to Formula
A208A wherein -E-E- corresponds to Formula XLIII, XLIV,
XLV or XLVII.
A compound of Formula A208C corresponds to Formula
A208 wherein RB° and R9° together with the ring carbon to
which they are attached comprise keto or:
Y2
Y~
jc\~ 7) mn( cH2) 2 - ~ - x HIV
where X, Yl, YZ and C(17) are as defined above.
Compounds of Formulae 208D correspond to Formula
208C in which the substituent XXXIV corresponds to the
structure XXXIII
0
0
m n XXXI I I
..... .. ,:.. .,..... ,. ..:,.:., .:.. . .. ... .... i
CA 02550897 1997-12-11
Compounds of Formulae A208E, A208F, A208G, A208H and
A208J respectively correspond to Formula A208, A208A,
A2088, A208C and A208D wherein each of -A-A- and
-B-B- is -CHZ-CH2-, and R3 is hydrogen. Compounds within
5 the scope of Formula A208 Gan be prepared by thermal
decomposition of corresponding compounds of Formula A207.
A compound of Formula A209 corresponds to the
structure:
R~ eo
_Reo
=v=
O-='
off [A209]
10 wherein Rg° and R9° are as def fined in Formula XLI , and
-E-E- and -A-A-, -B-B-, and R3 are as defined in Formula
205.
A compound of Formula A209A corresponds to Formula
A209 wherein R=1 and Rzz are independently selected from
15 among hydrogen, halogen, and lower alkyl.
A compound of Formula A209B corresponds to Formula
A209A wherein -E-E- corresponds to Formula XLIiI, XLIV,
XLV or XLVII.
A compound of Formula A209C corresponds to Formula
20 A209B wherein -E-E- corresponds to Formula XLIV.
A compound of Formula A209D corresponds to Formul a
A208 wherein RB° and R9° together with the ring carbon to
which they are attached comprise keto or:
Ys .
Y'
jC\1 7) VIII( Chl2) z - C ~ X
XXXIV
25 where X, Y1, YZ and C(17) are as defined above.
CA 02550897 1997-12-11
31
Compounds of Formulae 209E correspond to Formula
A209D in which the substituent XXXIV corresponds to the
structure XXXIII
0
0
,nn XXXIII
Compounds of Formulae A209F, A209G, A209Fi, A209J,
A209L, and A209M respectively correspond to Formula A209,
A209A, A209B, A209C, A209D and A209E wherein each of -A-
A- and -B-B- is -CH2-CHZ-, and R3 is hydrogen. Compounds
within the scope of Formula A209 may be prepared by
hydrolysis of a corresponding compound of Formula A208.
A compound of Formula A2lo corresponds to the
structure:
R9 010
RIo
1
OH [A210
wherein RI° and R9° are as defined in Formula XLI, and the
substituents -A-A-, -B-B- and R3 are as defined in Formula
IV.
A compound of Formula A210A corresponds to Formula
A210 wherein RB° and R9° together with the ring carbon to
which they are attached comprise keto or:
Yp
Y~C\1 7) VIII( CHq) 2 _ C ~ X
XXXIV
wherein X, Yl , Y2 and C ( 17 ) are as defined above .
. .. . i
CA 02550897 1997-12-11
32
Compounds of Formulae A210B correspond to Formula
A210A in which the substituent XXXIV corresponds to the
structure XXXIII
0
0
,11n XXXIII
Compounds of Formula A210C correspond to Formula
A210A in which Re° and R9° together form keto.
Compounds of Formulae A210D, A210E, A210F and A210G
respectively correspond to Formula A210, A210A, A210B and
A210C wherein each of -A-A- and -B-B- is
-CHz-CHz- and and R3 is hydrogen. Compounds within the
scope of Formula 210 can be prepared by epoxidation of a
compound of Formula 209 in which -E-E- is ~° - c"..
A compound of Formula A211 corresponds to the
Formula
R3 ao
. R R°o
B
i
B
v = v -__
O
0
[A211
where -A-A-, -B-B- and R3 are as described above.
A compound of Formula A211A corresponds to Formula
A211 wherein R8° and R9° together comprise keto or:
Y2
C( 1 7) 11111( CHz) 2 ' C ~ X
\ XXXIV
2 0 wherein X, Y1, YZ and C ( 17 ) are as def fined above .
Compounds of Formulae A211B correspond to Formula
A211A in which the substituent XXXIV corresponds to the
structure XXXIII
..,.._ .. . I
CA 02550897 1997-12-11
33
0
XXXIII
Compounds of Formula A211C correspond to Formula
A211A in which Re° and R'° together form keto.
Compounds of Formulae A211D, A211E, A211F, and
A211G, respectively correspond to Formula A211; A211A,
A211B and A211C wherein each of -A-A- and -H-H- is
-CHI-CHZ-, and R' is hydrogen. Compounds within the scope
of Formula A211 can be prepared by oxidation of a
corresponding compound of Formula A210; or in the course
of epoxidation of the corresponding compound of Formula
A209 where -.E-E- is ~~ ~ ~H . Compounds of Formula A211
may be converted to compounds of Formula I in the manner
described hereinbelow. .
A compound of Formula L corresponds to the
structure:
Ra R~
~ \ _R~
B
O AiA B
Rtt/\O \ \ i,~~Rt
L
wherein Rll is Cl to C, alkyl, and -A-A-, -H-H-, R', R~; R',
Re and R9 are as def fined above .
Compounds of Formula LA correspond to Formula L
wherein R8 and R9 together with the carbon atom to which
they are attached comprises
Yz
Yt
~C\1 7) iiiu( ChIZ) z - C
XXXIV
CA 02550897 1997-12-11
34
wherein X, Y1 and Y~ are as defined above .
Compounds of Formula LB correspond to Formula L
wherein Re and R9 correspond to Formula XXXIII
0
0 >
XXXIII
Compounds of Formulae LC, LD, LE correspond to
Formulae L, LA and LH, respectively, where -A-A- and
-B-B- are each -CHZ-CHZ- and R3 is hydrogen.
Based on the disclosure of specific reaction schemes
as set out hereinbelow, it will be apparent which of
these compounds have the greatest utility relative to a
particular reaction scheme. The compounds of this
invention are useful as intermediates for epoxymexrenone
and other steroids.
Other objects and features will be in part apparent
and in part pointed out hereinafter.
Brief Description of the Drawings '
Fig. 1 is a schematic flow sheet of a process for
the bioconversion of canrenone or a canrenone derivative
to the corresponding lla-hydroxy compound;
Fig. 2 is a schematic flow sheet of a preferred
process for the bioconversion/11-a-hydroxylation of
canrenone and canrenone derivatives;
Fig. 3 is a schematic flow sheet of a particularly
preferred process for the bioconversion/
11-a-hydroxylation of canrenone and canrenone
derivatives;
Fig. 4 shows the particle size distribution for
canrenone as prepared in accordance with the process of
Fig. 2; and
CA 02550897 1997-12-11
Fig. 5 shows the particle size distribution for
canrenone as sterilized in the transformation fermenter
in accordance with the process of Fig. 3.
Corresponding reference characters indicate
5 corresponding parts throughout the drawings.
Description of the Preferred Embodiments
In accordance with the present invention, various
novel process schemes have been devised for the
preparation of epoxymexrenone and other compounds
10 corresponding Formula I:
R3 Re
I v R9
B
8
iiii R 1
I
wherein:
-A-A- represents the group -CHR9-CHRS- or
-CR4=CRS- ;
15 R3, R' and RS are independently selected from the
group consisting of hydrogen, halo, hydroxy, lower
alkyl, lower alkoxy, hydroxyalkyl, alkoxyalkyl,
hydroxycarbonyl, cyano and aryloxy;
R1 represents an alpha-oriented lower alkoxycarbonyl
20 or hydroxyalkyl radical; and
-B-B- represents the group -CHR6-CHR'- or an alpha-
or beta- oriented group:
Re R~
CH CH
CH-CH2-CH- III
.. , i
CA 02550897 1997-12-11
36
where R6 and R' are independently selected from the
group consisting of hydrogen, halo, lower alkoxy,
acyl, hydroxyalkyl, alkoxyalkyl, hydroxycarbonyl,
alkyl, alkoxycarbonyl, acyloxyalkyl, cyano and
aryloxy; and
R8 and R9 are independently selected from the group
consisting of hydrogen, hydroxy, halo, lower alkoxy,
acyl, hydroxyalkyl, alkoxyalkyl, hydroxycarbonyl,
alkyl, alkoxycarbonyl, acyloxyalkyl, cyano and
aryloxy, or R8 and R9 together comprise a carbocyclic
or heterocyclic ring structure, or RB or R9 together
with Rs or R' comprise a carbocyclic or heterocyclic
ring structure fused to the pentacyclic D ring.
Unless stated otherwise, organic radicals referred
to as "lower" in the present disclosure contain at most
7, and preferably from 1 to 4, carbon atoms.
A lower alkoxycarbonyl radical is preferably one
derived from an alkyl radical having from 1 to 4 carbon
atoms, such as methyl, ethyl, propyl, isopropyl, butyl,
isobutyl, sec.-butyl and tert.-butyl; especially
preferred are methoxycarbonyl,.ethoxycarbonyl and
isopropoxycarbonyl. A Lower alkoxy radical is preferably
one derived from one of the above-mentioned C1-C, alkyl
radicals, especially from a primary C1-C4 alkyl radical;
especially preferred is methoxy. A lower alkanvyl
radical is preferably one derived from a straight-chain
alkyl having from 1 to 7 carbon atoms; especially
preferred are formyl and acetyl.
A methylene bridge in the 15,16-position is
preferably ,Q-oriented.
A preferred class of compounds that may be produced
in accordance with the methods of the invention are the
20-spiroxane compounds described in U.S. patent
4,559,332, i.e., those corresponding to Formula IA:
CA 02550897 1997-12-11
37
Y2
1
H3C Y vvCCH2)2-C-X
ii ~
i
A CH3\\\\0 /B
/ i~~~ R 1
IA
where:
-A-A- represents the group -CHZ-CHZ- or -CH=CH-;
-B-H- represents the group -CHZ-CH2- or an alpha- or
beta- oriented group of Formula IIIA:
-CH-CHZ-CH- IIIA
R1 represents an alpha-oriented lower alkoxycarbonyl
or hydroxycarbonyl radical;
X represents two hydrogen atoms, oxo or =S;
Yl and YZ together represent the oxygen bridge
-O-, or
Y1 represents hydroxy, and
Y2 represents hydroxy, lower alkoxy or, if X
represents H2, also lower alkanoyloxy.
Preferably, 20-spiroxane compounds produced by the
novel methods of the invention are those of Formula I in
which Y1 and YZ together represent the oxygen bridge
-p_.
Especially preferred compounds of the formula I are
those in which X represents oxo. Of compounds of the 20-
spiroxane compounds of Formula IA in which X represents
oxo, there are most especially preferred those in which Yl
together with Y2 represents the oxygen bridge -O-.
As already mentioned, 17~i-hydroxy-21-carboxylic acid
may also be in the form of their salts. There come into
consideration especially metal and ammonium salts, such
as alkali metal and alkaline earth metal salts, for
example sodium, calcium, magnesium and, preferably,
CA 02550897 1997-12-11
38
potassium salts, and ammonium salts derived from ammonia
or a suitable, preferably physiologically tolerable,
organic nitrogen-containing base. As bases there come
into consideration not only amines,.for example lower
alkylamines (such as triethylamine), hydroxy-lower
alkylamines (such as 2-hydroxyethylamine, di-(2-
hydroxyethyl)-amine or tri-(2-hydroxyethyl)-amine),
cycloalkylamines (such as dicyclohexylamine) or
benzylamines (such as benzylamine and N,N'-
dibenzylethylenediamine), but also nitrogen-containing
heterocyclic compounds, for example those of aromatic
character (such as pyridine or quinoline) or those having
an at least partially saturated heterocyclic ring (such
as N-ethylpiperidine, morpholine, piperazine or N,N'-
dimethylpiperazine).
Also included amongst preferred compounds are alkali
metal salts, especially potassium salts, of compounds of
the formula IA in which R1 represents alkoxycarbonyl, with
X representing oxo and each of Yl and YZ representing
hydroxy.
Especially preferred compounds of the formula I and
IA are, for example, the following:
9a,lla-epoxy-7a-methoxycarbonyl-20-spirox-4-ene-
3,21-dione,
9a,lla-epoxy-7a-ethoxycarbonyl-20-spirox-4-ene-3,21-
dione,
9a,lla-epoxy-7a-isopropoxycarbonyl-20-spirox-4-ene-
3,21-dione,
and the 1,2-dehydro analogue of each of the
compounds;
9a,lla-epoxy-6a,7a-methylene-20-spirox-4-ene-3,21-
dione,
9a,lla-epoxy-6R,7~i-methylene-20-spirox-4-ene-3,21-
dione,
9a, lla-epoxy-6,Q, 7Q; 15,Q, 16,x-bismethylene-20-spirox-4-
ene-3,21-dione,
CA 02550897 1997-12-11
39
and the 1,2-dehydro analogue of each of these
compounds;
9a,lla-epoxy-7a-methoxycarbonyl-17(3-hydroxy-3-oxo-
pregn-4-ene-21-carboxylic acid,
9a,lla-epoxy-7a-ethoxycarbonyl-17Q-hydroxy-3-oxo-
pregn-4-ene-21-carboxylic acid,
9a,lla-epoxy-7a-isopropoxycarbonyl-17~i-hydroxy-3-
oxo-pregn-4-ene-21-carboxylic acid,
9a,lla-epoxy-173-hydroxy-6a,7a-methylene-3-oxo-
pregn-4-ene-21-carboxylic acid,
9a, lla-epoxy-17Q-hydroxy-6~i, 7~i-methylene-3 -oxo-
pregn-4-ene-21-carboxylic acid,
9a, lla-epoxy-17 f3-hydroxy-6~i, 7~i;15~i, 16~i-bismethylene-
3-oxo-pregn-4-ene-21-carboxylic acid,
and alkali metal salts, especially the potassium
salt or ammonium of each of these acids, and also a
corresponding 1,2-dehydro analogue of each of the
mentioned carboxylic acids or of a salt thereof;
9a,lla-epoxy-15Q,16(3-methylene-3,21-dioxo-20-spirox-
4-ene-7a-carboxylic acid methyl ester, ethyl ester and
isopropyl ester,
9a;lla-epoxy-1565f3,16~i-methylene-3,21-dioxo-20
spiroxa-1,4-diene-7a-carboxylic acid methyl ester, ethyl
ester and isopropyl ester,
9a,lla-epoxy-3-oxo-20-spirox-4-ene-7a-carboxylic
acid methyl ester, ethyl ester and isopropyl ester,
9a,lla-epoxy-6,(i,6~i-methylene-20-spirox-4-en-3-one,
9a,lla-epoxy-6Q,7/3;15~i,16~i-bismethylene-20-spirox-4-
en-3-one,
9a,lla-epoxy,l7~i-hydroxy-17x(3-hydroxy-propyl)-3-
oxo-androst-4-ene-7a-carboxylic acid methyl ester, ethyl
ester and isopropyl ester,
9a,lla-epoxy,l7~i-hydroxy-17a-(3-hydroxypropyl)-
6a,7a-methylene-androst-4-en-3-one,
9a,lla-epoxy-17,Q-hydroxy-17a-(3-hydroxypropyl)-
6Q,7~i-methylene-androst-4-er.-3-one,
CA 02550897 1997-12-11
9a,lla-epoxy-17~i-hydroxy-17a-(3-hydroxypropyl)-
6~i, 7/3;15Q,16~i-bismethylene-androst-4-en-3-one,
including 17a-(3-acetoxypropyl) and 17x-(3-
fromyloxypropyl) analogues of the mentioned androstane
5 compounds,
and also 1,2-dehydro analogues of all the mentioned
compounds of the androst-4-en-3-one and 20-spirox-4-en-3-
one series.
The chemical names of the compounds of the Formulae
10 I and IA, and of analogue compounds having the same
characteristic structural features, are derived according
to current nomenclature in the following manner: for
compounds in which Y1 together with YZ represents -O-,
from 20-spiroxane (for example a compound of the formula
15 IA in which X represents oxo and Y1 together with Yz
represents -O- is derived from 20-spiroxan-21-one); for
those in which each of Y1 and YZ represents hydroxy and X
represents oxo, from 17(3-hydroxy-17a-pregnene-21-
carboxylic acid; and for those in which each of Yl and YZ
20 represents hydroxy and X represents two hydrogen atoms,
from 17(3-hydroxy-17a-(3-hydroxypropyl)-androstane. Since
the cyclic and open-chain forms, that is to say lactones
and 17Q-hydroxy-21-carboxylic acids and their salts,
respectively, are so closely related to each other that
25 the latter may be considered merely as a hydrated form of
the former, there is to be understood hereinbefore and
hereinafter, unless specifically stated otherwise, both
in end products of the formula I and in starting
materials and intermediates of analogous structure, in
30 each case all the mentioned forms together.
In accordance with the invention, several separate
process schemes have been devised for the preparation of
compounds of Formula I in high yield and at reasonable
cost. Each of the synthesis schemes proceeds through the
35 preparation of a series of intermediates. A number of
these intermediates are novel compounds, and the methods
CA 02550897 1997-12-11
41
of preparation of these intermediates are novel
processes.
Scheme 1 (Starting With Canrenone or Related Material,
One preferred process scheme for the preparation of
compounds of Formula I advantageously begins with
canrenone or a related starting material corresponding to
Formula XIII (or, alternatively, the process can begin
with androstendione or a related starting material)
R3
n8
Rg
3
XIII
wherein
-A-A- represents the group -CHR'-CHRS- or
-CR'=CRS- ;
R3, R' and RS are independently selected from the
group consisting of hydrogen, halo, hydroxy; lower
alkyl, lower alkoxy, hydroxyalkyl, alkoxyalkyl,
hydroxycarbonyl, cyano and aryloxy;
-B-B- represents the group -CHR6-CHR'- or an alpha-
or beta- oriented group:
Ft s
\ ~
CH CH
-CH-CH2-CH- III
where R6 and R' are independently selected from the
group consisting of hydrogen, halo, lower alkoxy,
acyl, hydroxyalkyl, alkoxyalkyl, hydroxycarbonyl,
alkyl, alkoxycarbonyl, acyloxyalkyl, cyano and
aryloxy; and
CA 02550897 1997-12-11
42
Re and R9 are independently selected from the group
consisting of hydrogen, hydroxy, halo, lower alkoxy,
acyl, hydroxyalkyl, alkoxyalkyl, hydroxycarbonyl,
alkyl, alkoxycarbonyl, acyloxyalkyl, cyano and
aryloxy, or RB and R' together comprise a keto,
carbocyclic or heterocyclic ring structure, or RB and
R9 together with R6 or R' comprise a carbocyclic or
heterocyclic ring structure fused to the pentacyclic
D ring .
to Using a bioconversion process of the type
illustrated in Figs. 1 and 2, an ll-hydroxy group of a-
orientation is introduced in the compound of Formula
XIII, thereby producing a compound of Formula VIII:
A3 Re
1 ~
8
B
VIII
where -A-A- , -B-B- , R' , Re and R9 are as def fined in
Formula XIII. Preferably, the compound of Formula XIII
has the structure
R3 Y2
Y~
2~ 2 C-X
B
8
XIIIA
and the lla-hydroxy product has the structure
CA 02550897 1997-12-11
43
Y2
p3
H3~ Y CH )-C-X
H0 w~~ 2 2
////
CH3 B
AiA 8
VIIIA
in each of which
-A-A- represents the group -CHZ-CHZ- or -CH=CH-;
-B-B- represents the group -CHZ-CHZ- or an alpha- or
beta- oriented group:
-CH-CHZ-CH- IIIA
R3 is hydrogen, lower alkyl or lower alkoxy;
X represents two hydrogen atoms, oxo or =S;
Yl and YZ together represent the oxygen bridge
-0-, or
Y1 represents hydroxy, and
YZ represents hydroxy, lower alkoxy or, if X
represents H2, also lower alkanoyloxy;
and salts of compounds in which X represents oxo and Y2
represents hydroxy. More preferably, the compound of
Formula VIIIA produced in the reaction corresponds to a
compound of Formula VIIIA wherein -A-A- and -B-B- are
each -CHZ-CH2-; R3 is hydrogen; Y1, Y2, and X are as
defined in Formula XIIIA; and Re and R9 together form the
20-spiroxane structure:
0
0
n XXXIII.
Among the preferred organisms that can be used in
this hydroxylation step are AsperQillus ochraceus NRRL
CA 02550897 1997-12-11
44
405, Asneraillus ochraceus ATCC 18500, Asperaillus nicer
ATCC 16888 and ATCC 26693, As~eraillus nidulans ATCC
11267, Rhizopus orvzae ATCC 11145, Rhizo~us stolonifer
ATCC 6227b, Stre~tomvces fradiae ATCC 10745, Bacillus
megaterium ATCC 14945, Pseudomonas cruciviae ATCC 13262,
and Trichothecium roseum ATCC 12543. Other preferred
organisms include Fusarium oxvsporum f.sg.cepae ATCC
11171 and Rhizopus arrhizus ATCC 11145.
Other organisms that have exhibited activity for
this reaction include Absidia coerula ATCC 6647, Absidia
glauca ATCC 22752, Actinomucor eleaans ATCC 6476,
AsDeraillus flaviDes ATCC 1030, As~eraillus fumiaatus
ATCC 26934, Heauveria bassiana ATCC 7159 and ATCC 13144,
Botrvosyhaeria obtusa IMI 038560, Calonectria decora
ATCC 14767; Chaetomium cochliodes ATCC 10195, Corvnespora
cassiicola ATCC 16718, Cunninahamella blakesleeana ATCC
8688a, Cunninahamella echinulata ATCC 3655,
Cunninahamella elegans ATCC 9245, Curvularia clavata
ATCC 22921, Curvularia lunata ACTT 12017, Cvlindrocarnon
radicicola ATCC 1011, Epicoccum humicola ATCC 12722,
Gonaronella butleri ATCC 22822, Fivnomvces chrysospermus
ATCC IMI 109891, Mortierella isabellina ATCC 42613, Mucor
mucedo ATCC 4605, Mucor griseo-cvanus ATCC 1207A,
Mvrothecium verrucaria ATCC 9095, Nocardia corallina ATCC
19070, Paecilomvces carneus ATCC 46579, Penicillum
patulum ATCC 24550, Pithomvces atro=olivaceus IFO 6651,
Pithomyces cynodontis ATCC 26150, Pycnosoorium sue. ATCC
12231, Saccharopolvspora ervthrae ATCC 11635, SeDedonium
chrvsosgermum ATCC 13378, Stachylidium bicolor ATCC
12672, Strentomvces hvgrosco~~icus ATCC 27438,
Streptomvces ~urnurascens ATCC 25489, Svnce~halastrum
racemosum ATCC 18192, Thamnostylum~iriforme ATCC 8992,
Thielavia terricola ATCC 13807, and Verticillium
theobromae ATCC 12474.
Additional organisms that may be expected to show
activity for the lla-hydroxylation include Ce~halosporium
CA 02550897 1997-12-11
a~hidicola (Phytochemistry (1996), 42(2), 411-415),
Cochliobolus lunatas (J. Biotechnol. (1995) , 42 (2) , 145-
150), Tieahemella orchidis (Khim.-Farm.Zh. (1986),
20(7), 871-876), Tie4hemella hyalospora (Khim.-Farm.Zh.
5 (1986), 20(7), 871-876), Monosporium olivaceum (Acta
Microbiol. Pol., Ser. B. (1973), 5(2), 103-110),
Aspercrillus ustus (Acta Microbiol. Pol., Ser. B.' (1973) ,
5(2), 103-110), Fusarium Qraminearum (Acta Microbiol.
Pol., Ser. B. (1973), 5(2), 103-110), Verticillium
10 Qlaucum (Acta Microbiol . Pol . , Ser. B. (1973) , 5 (2) , 103-
110), and Rhizopus niqricans (J. Steroid Biochem. (1987),
28 (2) , 197-201) .
The 11(3-hydroxy derivatives of androstendione and
mexrenone can be prepared according to the bioconversion
15 processes set forth in Examples 19A and 19B,
respectively. The inventors hypothesize by analogy that
the corresponding (3-hydroxy isomer of the compound of
Formula VIII having a C11 R-hydroxy substituent instead
of a C11 a-hydroxy substituent can also be prepared using
20 a similar bioconversion process employing suitable
microorganisms capable of carrying out the 11~-
hydroxylation, such as one or more of the microorganisms
disclosed herein.
Preparatory to production scale fermentation for
25 hydroxylation of canrenone or other substrates of Formula
XIII, an inoculum of cells is prepared in a seed
fermentation system comprising a seed fermenter, or a
series of two or more seed fermenters. A working stock
spore suspension is introduced into the first seed
30 fermenter, together with a nutrient solution for growth
of cells. If the volume of inoculum desired or needed
for production exceeds that produced in the first seed
fermenter, the inoculum volume may be progressively and
geometrically amplified by progression through the
35 remaining fermenters in the seed fermentation train.
Preferably, the inoculum produced in the seed
CA 02550897 1997-12-11
46
fermentation system is of sufficient volume and viable
cells for achieving rapid initiation of reaction in the
production fermenter, relatively short production batch
cycles, and high production fermenter activity. Whatever
the number of vessels in a train of seed fermenters, the _
second and subsequent seed fermenters are preferably
sized so that the extent of dilution at each step in the
train is essentially the same. The initial dilution of
inoculum in each seed fermenter can be approximately the
same as the dilution in the production fermenter.
Canrenone or other Formula XIII substrate is charged to
the production fermenter along with inoculum and nutrient
solution, and the hydroxylation reaction conducted there.
The spore suspension charged to the seed
fermentation system is from a vial of working stock spore
suspension taken from a plurality of vials constituting a
working stock cell bank that is stored under cryogenic
conditions prior to use. The working stock cell bank is
in turn derived from a master stock cell bank that has
been prepared in the following manner. A spore specimen
obtained from an appropriate source, e.g., ATCC, is
initially suspended in an aqueous medium such as, for
example, saline solution, nutrient solution or a
surfactant solution, (e.g., a nonionic surfactant such as
Tween 20 at a concentration of about 0.001% by weight) ,
and the suspension distributed among culture plates, each
plate bearing a solid nutrient mixture, typically based
on a non-digestible polysaccharide such as agar, where
the spores are propagated. The solid nutrient mixture
preferably contains between about 0.5% and about 5% by
weight glucose, between about 0.05% and about 5% by
weight of a nitrogen source, e.g., peptone, between about
0.05% and about 0.5% by weight of a phosphorus source,
e.g., an ammonium or alkali metal phosphate such as
dipotassium hydrogen phosphate, between about 0.25% and
about 2.5% by weight yeast lysate or extract (or other
CA 02550897 1997-12-11
47
amino acid source such as meat extract or brain heart
infusion), between about 1% and about 2% by weight agar
or other non-digestible polysaccharide. Optionally, the
solid nutrient mixture may further comprise and/or
contain between about 0.1% and about 5% by weight malt
extract. The pH of the solid nutrient mixture is
preferably between about 5.0 and about 7.0, adjusted as
required by alkali metal hydroxide or orthophosphoric
acid. Among useful solid growth media are the following:
1. Solid Medium #1: 1% glucose, 0.25% yeast extract,
0 . 3 % KzHP04 , and 2 % agar (Bacto ) ; pH
adjusted to 6.5 with 20% NaOH.
2. Solid Medium #2: 2% peptone (Bacto), 1% yeast
extract (Bacto), 2% glucose, and 2%
agar (Bacto); pH adjusted to 5 with
10% H3P0, .
3. Solid Medium #3: 0.1% peptone (Bacto), 2% malt
extract (Bacto), 2% glucose, and 2%
agar (Bacto); pH as is 5_3.
4. Liquid Medium: 5% blackstrap molasses, 0.5%
cornsteep liquor, 0.25% glucose,
0.25% NaCl, and 0.5% KHZP04, pH
adjusted to 5.8.
5. Difco Mycological agar (low pH).
The number of agar plates used in the
development of a master stock cell bank can be selected
with a view to future demands for master stock, but
typically about 15 to about 30 plates are so prepared.
After a suitable period of growth, e.g., 7 to 10 days,
the plates are scraped in the presence of an aqueous
vehicle, typically saline or buffer, for harvesting the
spores; and the resulting master stock suspension is
divided among small vials, e.g., one ml. in each of a
plurality of 1.5 ml vials. To prepare a working stock
spore suspension for use in research or production
fermentation operations, the contents of one or more of
CA 02550897 1997-12-11
48
these second generation master stock vials can be
distributed among and incubated on agar plates in the
manner described above for the preparation of master
stock spore suspension. Where routine manufacturing
operations are contemplated, as many as 100 to 400 plates
may be used to generate second generation working stock.
Each plate is scraped into a separate working stock vial,
each vial typically containing one ml of the inoculum
produced. For permanent preservation, both the master
stock suspension and the second generation production
inoculum are advantageously stored in the vapor space of
a cryogenic storage vessel containing liquid NZ or other
cryogenic liquid.
In the process illustrated in Fig. 1, aqueous
growth medium is prepared which includes a nitrogen
source such as peptone, a yeast derivative or equivalent,
glucose, and a source of phosphorus such as a phosphate
salt. Spores of the microorganism are cultured in this
medium in the seed fermentation system. The preferred
microorganism is As_perQillus ochraceus NRRL 405 (ATCC
18500). The seed stock so produced is then introduced
into the production fermenter together with the substrate
of Formula XIII. The fermentation broth is agitated and
aerated for a time sufficient for the reaction to proceed
to the desired degree of completion.
The medium for the seed fermenter preferably
comprises an aqueous mixture which contains: between
about 0.5% and about 5% by weight glucose, between about
0.05% and about 5% by weight of a nitrogen source, e.g.,
peptone, between about 0.05% and about 0.5% by weight of
a phosphorus source, e.g., an ammonium or alkali metal
phosphate such as ammonium phosphate monobasic or
dipotassium hydrogen phosphate, between about 0.25% and
about 2.5% by weight yeast lysate or extract (or other
amino acid source such as distiller's solubles), between
about 1% and about 2% by weight agar or other non-
CA 02550897 1997-12-11
49
digestible polysaccharide. A particularly preferred seed
growth medium contains about 0.05% and about 5% by weight
of a nitrogen source such as peptone, between about 0.25%
and about 2.5% by weight of autolyzed yeast or yeast
extract, between about 0.5% and about 5% by weight
glucose, and between about 0.05% by weight and about 0.5%
by weight of a phosphorus source such as ammonium
phosphate monobasic. Especially economical process
operations are afforded by the use of another preferred
seed culture which contains between about 0.5% and about
5% by weight corn steep liquor, between about 0.25% and
about 2.5% autolyzed yeast or yeast extract, between
about 0.5% and about 5% by weight glucose and about 0.05%
and about 0.5% by weight ammonium phosphate monobasic.
Corn steep liquor is a particularly economical source of
proteins, peptides, carbohydrates, organic acids;
vitamins, metal ions, trace matters and phosphates. Mash
liquors from other grains may be used in place of, or in
addition to, corn steep liquor. The pH of the medium is
preferably adjusted within the range of between about 5.0
and about 7.0, e.g., by addition of an alkali metal
hydroxide or orthophosphoric acid. Where corn steep
liquor serves as the source of nitrogen and carbon, the
pH is preferably adjusted within the range of about 6.2
to about 6.8. The medium comprising peptone and glucose
is preferably adjusted to a pH between about 5.4 and
about 6.2. Among useful growth media for use in seed
fermentation:
1. Medium #1: 2% peptone, 2% yeast autolyzed (or yeast
extract), and 2% glucose; pH adjusted to
5.8 with 20% NaOH.
2. Medium #2: 3% corn steep liquor, 1.5% yeast extract,
0.3% ammonium phosphate monobasic, and 3%
glucose; pH adjusted to 6.5 with 20%
NaOH.
CA 02550897 1997-12-11
Spores of the microorganism are introduced into
this medium from a vial typically containing in the
neighborhood of 109 spores per ml. of suspension. Optimal
productivity of seed generation is realized where
5 dilution with growth medium at the beginning of a seed
culture does not reduce the spore population density
below about 10' per ml. Preferably, the spores are
cultured in the seed fermentation system until the packed
mycelial volume (PMV) in the seed fermenter is at least
10 about 20%, preferably about 35% to about 45%. Since the
cycle in the seed fermentation vessel (or any vessel of a
plurality which comprise a seed fermentation train)
depends on the initial concentration in that vessel, it
may. be desirable to provide two or three seed
15 fermentation stages to accelerate the overall process.
However, it is preferable to avoid the use of
significantly more than three seed fermenters in series,
since activity may be compromised if seed fermentation is
carried through an excessive number of stages. The seed
20 culture fermentation is conducted under agitation at a
temperature in the range of about 23° to about 37°C,
preferably in range of between about 24° and about 28°C.
Culture from the seed fermentation system is
introduced into a production fermenter, together with a
25 production growth medium. In one embodiment of the
invention, non-sterile canrenone or other substrate of
Formula XIII serves as the substrate for the reaction.
Preferably, the substrate is added to the production
fermenter in the form of a 10% to 30% by weight slurry in
30 growth medium. To increase the surface area available
for lla-hydroxylation reaction, the particle size of the
Formula XIII substrate is reduced by passing the
substrate through an off line micronizer prior to
introduction into the fermenter. A sterile nutrient feed
35 stock containing glucose, and a second sterile nutrient
solution containing a yeast derivative such as autolyzed
CA 02550897 1997-12-11
51
yeast (or equivalent amino acid formulation based on
alternative sources such as distiller's solubles), are
also separately introduced. The medium comprises an
aqueous mixture containing: between about 0.5% and about
5% by weight glucose, between about 0.05% and about 5% by
weight of a nitrogen source, e.g., peptone, between about
0.05% and about 0.5% by weight of a phosphorus source,
e.g., an ammonium or alkali metal phosphate such as
dipotassium hydrogen phosphate, between about 0.25% and
l0 about 2.5% by weight yeast lysate or extract (or other
amino acid source such as distiller's solubles), between
about 1% and about 2% by weight agar or other non-
digestible polysaccharide. A particularly preferred
production growth medium contains about 0.05% acrd about
5% by weight of a nitrogen source such as peptone,
between'about 0.25% and about 2.5% by weight of autolyzed
yeast or yeast extract, between about 0.5% and about 5%
by weight glucose, and between about 0.05% and about 0.5%
by weight of a phosphorus source such as ammonium
phosphate monobasic. Another preferred production medium
contains between about 0.5% and about 5% by weight corn
steep liquor, between about 0.25% and about 2.5%
autolyzed yeast or yeast extract, between about 0.5% and
about 5% by weight glucose and about 0.05% and about 0.5%
by weight ammonium phosphate monobasic. The pFi of the
production fermentation medium is preferably adjusted in
the manner described above for the seed fermentation
medium, with the same preferred ranges for the pH of
peptone/glucose based media and corn steep liquor based
media, respectively. Useful bioconversion growth media
are set forth below:
1. Medium #1: 2% peptone, 2% yeast autolyzed (or yeast
extract), and 2% glucose; pH adjusted to
5.8 with 20°s NaOH.
CA 02550897 1997-12-11
52
2. Medium #2: 1% peptone, 1% yeast autolyzed (or yeast
extract), and 2% glucose; pH adjusted to
5.8 with 20% NaOH.
3. Medium #3: 0.5% peptone, 0.5% yeast autolyzed (or
yeast extract), and 0.5% glucose; pH
adjusted to 5.8 with 20% NaOH.
4. Medium #4: 3% corn steep liquor, 1.5% yeast
extract, 0.3% ammonium phosphate
monobasic, and 3% glucose; pH adjusted
to 6.5 with 20% NaOH.
5. Medium #5: 2.55% corn steep liquor, 1.275% yeast
extract, 0.255% ammonium phosphate
monobasic, and 3% glucose; pH adjusted
to 6.5 with 20% NaOH.
6. Medium #6: 2.1% corn steep liquor, 1.05% yeast
extract, 0.21% ammonium phosphate
monobasic, and 3% glucose; pH adjusted
to 6.5 with 20% NaOH.
Non-sterile canrenone and sterile nutrient
solutions are chain fed to the production fermenter in
about five to about twenty, preferably about ten to about
fifteen, preferably substantially equal, portions each
over the production batch cycle. Advantageously, the
substrate is initially introduced in an amount sufficient
to establish a concentration of between about 0.1% by
weight and about 3% by weight, preferably between about
0.5% and about 2% by weight, before inoculation with seed
fermentation broth, then added periodically, conveniently
every 8 to 24 hours, to a cumulative proportion of
between about 1% and about 8% by weight. Where
additional substrate is added every 8 hour shift, total
addition may be slightly lower, e.g., 0.25% to 2.5% by
weight, than in the case where substrate is added only on
a daily basis. In the latter instance cumulative
canrenone addition may need to be in the range 2% to
about 8% by weight. The supplemental nutrient mixture
fed during the fermentation reaction is preferably a
concentrate, for example, a mixture containing between
CA 02550897 1997-12-11
53
about 40% and about 60% by weight sterile glucose, and
between about 16% and about 32% by weight sterile yeast
extract or other sterile source of yeast derivative (or
other amino acid source). Since the substrate fed to the
production fermenter of Fig. 1 is non-sterile,
antibiotics are periodically added to the fermentation
broth to control the growth of undesired organisms.
Antibiotics such as kanamycin, tetracycline, and
cefalexin can be added without disadvantageously
affecting growth and bioconversion. Preferably, these
are introduced into the fermentation broth in a
concentration, e.9., of between about 0.0004% and about
0.002% based, on the total amount of the broth,
comprising, e.g., between about 0.0002% and about 0.0006%
kanamicyn sulfate, between about 0.0002% and about 0.006%
tetracycline HC1 and/or between about 0.001% and about
0.003% cefalexin, again based on the total amount of
broth.
Typically, the production fermentation batch
cycle is in the neighborhood of about 80-160 hours.
Thus, portions of each of the Formula XIII substrates and
nutrient solutions are typically added about every 2 to
10 hours, preferably about every 4 to 6 hours.
Advantageously, an antifoam is also incorporated in the
seed fermentation system, and in the production
fermenter.
Preferably, in the process of Fig. 1, the
inoculum charge to the production fermenter is about 0.5%
to about 7%, more preferably about 1% to about 2%, by
volume based on the total mixture in the fermenter; and
the glucose concentration is maintained between about
0.01% and about 1.0%, preferably between about 0.025% and
about 0.5%, more preferably between about 0.05% and about
0.25% by weight with periodic additions that are
preferably in portions of about 0.05% to about 0.25% by
weight, based on the total batch charge. The
CA 02550897 1997-12-11
54
fermentation temperature is conveniently controlled
within a range of about 20° to about 37°C, preferably
about 24°C to about 28°C, but it may be desirable to step
down the temperature during the reaction, e.g., in 2°C
increments, to maintain the packed mycelium volume (PMV)
below about 60%, more preferably below about 50%, and
thereby prevent the viscosity of the fermentation broth
from interfering with satisfactory mixing. If the
biomass growth extends above the liquid surface,
substrate retained within the biomass may be carried out
of the reaction zone and become unavailable for the
hydroxylation reaction. For productivity, it is
desirable to reach a PMV in the range of 30 to 50%,
preferably 35% to 45%, within the first 24 hours of the
fermentation reaction, but thereafter conditions are
preferably managed to control further growth within the
limits stated above. During reaction, the pIi of the
fermentation medium is controlled at between about 5.0
and about 6.5, preferably between about 5.2 and about
5.8, and the fermenter is agitated at a rate of between
about 400 and about 800 rpm. A dissolved oxygen level of
at least about 10% of saturation is achieved by aerating
the batch at between about 0.2 and about 1.0 vvm, and
maintaining the pressure in the head space of the
fermenter at between about atmospheric and about 1.0 bar
gauge, most preferably in the neighborhood of about 0.7
bar gauge. Agitation rate may also be increased as
necessary to maintain minimum dissolved oxygen levels.
Advantageously, the dissolved oxygen is maintained at
well above about 10%, in fact as high as about 50% to
promote conversion of substrate. Maintaining the pH in
the range of 5.5~0.2 is also optimal for bioconversion.
Foaming is controlled as necessary by addition.of a
common antifoaming agent. After all substrate has been
added, reaction is preferably continued until the molar
ratio of Formula VIII product to remaining unreacted
CA 02550897 1997-12-11
Formula XIII substrate is at least about 9 to 1. Such
conversion may be achieve within the 80-160 hour batch
cycle indicated above.
It has been found that high conversions are
5 associated with depletion of initial nutrient levels
below the initial charge level, and by controlling
aeration rate and agitation rate to avoid splashing of
substrate out of the liquid broth. In the process of
Fig. 1, the nutrient level was depleted to and then
10 maintained at no greater than about 60%, preferably about
50%, of the initial charge level; while in the processes
of Figs. 2 and 3, the nutrient level was reduced to and
maintained at no greater than about 80%, preferably about
70%, of the initial charge level. Aeration rate is
15 preferably no greater than one vvm, more preferably in
the range of about 0.5 vvm; while agitation rate is
preferably not greater than 600 rpm.
A particularly preferred process for
preparation of a compound of Formula VIII is illustrated
20 in Fig. 2. A preferred microorganism for the lla-
hydroxylation of a compound of Formula XIII (for example,
canrenone) is Asoeraillus ochraceus NRRL 405 (ATCC
18500). In this process, growth medium preferably
comprises between about 0.5% and about 5% by weight corn
25 steep liquor, between about 0.5% and about 5% by weight
glucose, between about 0.1% and about 3% by weight yeast
extract, and between about 0.05% and about 0.5% by weight
ammonium phosphate. However, other production growth
media as described herein may also be used. The seed
30 culture is prepared essentially in the manner described
for the process of Fig. 1, using any of the seed
fermentation media described herein. A suspension of
non-micronized canrenone or other Formula XIII substrate
in the growth medium is prepared aseptically in a
35 blender, preferably at a relatively high concentration of
between about 10% and about 30% by weight substrate.
CA 02550897 1997-12-11
56
Preferably, aseptic preparation may comprise
sterilization or pasteurization of the suspension after
mixing. The entire amount of sterile substrate
suspension required for a production batch is introduced
into the production fermenter at the beginning of the
batch, or by periodical chain feeding. The particle size
of the substrate is reduced by wet milling in an on-line
shear pump which transfers the slurry to the production
fermenter, thus obviating the need for use of an off-line
micronizer: Where aseptic conditions are achieved by
pasteurization rather than sterilization, the extent of
agglomeration may be insignificant, but the,use of a
shear pump may be desirable to provide positive control
of particle size. Sterile growth medium and glucose
solution are introduced into the production fermenter
essentially in the same manner as described above. All
feed components to the production fermenter are
sterilized before introduction, so that no antibiotics
are required.
Preferably, in operation of the process of Fig.
2, the inoculum is introduced into the production
fermenter in a proportion of between about 0.5% and about
7%, the fermentation temperature is between about 20° and
about 37°.C, preferably between about 24°C and about
28°C,
and the pH is controlled between about 4.4 and about 6.5,
preferably between about 5.3 and about 5.5, e.g., by
introduction of gaseous ammonia; aqueous ammonium
hydroxide, aqueous alkali metal hydroxide, or
orthophosphoric acid. As in the process of Fig. 1, the
temperature is preferably trimmed to control growth of
the biomass so that PMV does not exceed 55-60%. The
initial glucose charge is preferably between about 1% and
about 4% by weight, most preferably 2.5% to 3.5% by
weight, but is preferably allowed to drift below about
1.0% by weight during fermentation. Supplemental glucose
is fed periodically in portions of between about 0.2% and
CA 02550897 1997-12-11
57
about 1.0% by weight based on the total batch charge, so
as to maintain the glucose concentration in the
fermentation zone within a range of between about 0.1%
and about 1.5% by weight, preferably between about 0.25%
and about 0.5% by weight. Optionally, nitrogen and
phosphorus sources may be supplemented along with
glucose. However, because the entire canrenone charge is
made at the beginning of the batch cycle, the requisite
supply of nitrogen and phosphorus bearing nutrients can
also be introduced at that time, allowing the use of only
a glucose solution for supplementation during the
reaction. The rate and nature of agitation is a
significant variable. Moderately vigorous agitation
promotes mass transfer between the solid substrate and
the aqueous phase. However, a low shear impeller should
be used to prevent degradation of the myelin of the
microorganisms. Optimal agitation velocity varies within
the range of 200 to 800 rpm, depending on culture broth
viscosity, oxygen concentration, and mixing conditions as
affected by vessel, baffle and impeller configuration.
Ordinarily, a preferred agitation rate is in the range of
350-600 rpm. Preferably the agitation impeller provides
a downward axially pumping function so as to assist in
good mixing of the fermented biomass. The batch is
preferably aerated at a rate of between about 0.3 and
about 1.0 vvm, preferably 0.4 to 0.8 vvm, and the
pressure in the head space of the fermenter is preferably
between about 0.5 and about 1.0 bar gauge. Temperature,
agitation, aeration and back pressure are preferably
controlled to maintain dissolved oxygen in the range of
at least about 10% by volume during the bioconversion.
Total batch cycle is typically between about 100 and
about 140 hours.
Although the principle of operation for the
process of Fig. 2 is based on early introduction of
substantially the entire canrenone charge, it will be~
CA 02550897 1997-12-11
58
understood that growth of the fermentation broth may be
carried out before the bulk of the canrenone is charged.
Optionally, some portion of the canrenone can also be
added later in the batch. Generally, however, at least
about 75% of the sterile canrenone charge shouhd be
introduced into the transformation fermenter within 48
hours after initiation of fermentation. Moreover, it is
desirable to introduce at least about 25% by weight
canrenone at~the beginning of the fermentation, or at
least within the first 24 hours in order to promote
generation of the bioconversion enzyme(s).
In a further preferred process as illustrated
in Fig. 3, the entire batch charge and nutrient solution
are sterilized in the production fermentation vessel
prior to the introduction of inoculum. The nutrient
solutions that may be used, as well as the preferences
among them, are essentially the same as in the process of
Fig. 2. In this embodiment of the invention, the
shearing action of the agitator impeller breaks down the
substrate agglomerates that otherwise tend to form upon
sterilization. It has been found that the reaction
proceeds satisfactorily if the mean particle size of the
canrenone is less than about 300 ~c and at least 75% by
weight of the particles are smaller than 240 ~C. The use
of a suitable impeller, e.g.,.a disk turbine impeller; at
an adequate velocity in the range of 200 to 80O rpm, with
a tip speed of at least about 400 cm/sec., has been found
to provide a shear rate sufficient to maintain such
particle size characteristics despite the agglomeration
that tends to occur upon sterilization within the
production fermenter. The remaining operation of the
process of Fig. 3 is essentially the same as the process
of Fig. 2. The processes of Figs. 2 and 3 offer several
distinct advantages over the process of Fig. 1. A
particular advantage is the amenability to use of a low
cost nutrient base such as corn steep liquor. But
CA 02550897 1997-12-11
59
further advantages are realized in eliminating the need
of antibiotics, simplifying feeding procedures, and
allowing for batch sterilization of canrenone or other
Formula XIII substrate. Another particular advantage is
the ability to use a simple glucose solution rather than
a complex nutrient solution for supplementation during
the reaction cycle.
In processes depicted in Figs. 1 to 3, the
product of Formula VIII is a crystalline solid which,
together with the biomass, may be separated from the
reaction broth by filtration or low speed centrifugation.
Alternatively, the product can be extracted from the
entire reaction broth with organic solvents. Product of
Formula VIII is recovered by solvent extraction. For
maximum recovery, both the liquid phase filtrate and the
biomass filter or centrifuge cake are treated with
extraction solvent, but usually x95 of the product is
associated with the biomass. Typically, hydrocarbon,
ester, chlorinated hydrocarbon, and ketone solvents may
2o be used for extraction. A preferred solvent is ethyl
acetate. Other typically suitable solvents include
toluene and methyl isobutyl ketone. For extraction from
the liquid phase, it may be convenient to use a volume of
solvent approximately equal to the volume of reaction
solution which it contacts. To recover product the from
the biomass, the latter is suspended in the solvent,
preferably in large excess relative to the initial charge
of substrate, e.g., 50 to 100 ml. solvent per gram of
initial canrenone charge, and the resulting suspension
preferably refluxed for a period of about 20 minutes to
several hours to assure transfer of product to the
solvent phase from recesses and pores of the biomass.
Thereafter, the biomass is removed by filtration or
centrifugation, and the filter cake preferably washed
with both fresh solvent and deionized water. Aqueous and
solvent washes are then combined and the phases allowed
CA 02550897 1997-12-11
to-separate. Formula VIII product is recovered by
crystallization from the solution. To maximize yield,
the mycelium is contacted twice with fresh solvent.
After settling to allow complete separation of the
5 aqueous phase, product is recovered from the solvent
phase. Most preferably, the solvent is removed under
vacuum until crystallization begins, then the
concentrated extract is cooled to a temperature of about
0° to about 20°C, preferably about 10° to about
15°C for
10 a time sufficient for crystal precipitation and growth,
typically about 8 to about 12 hours.
The processes of Fig. 2, and especially that of
Fig. 3, are particularly preferred. These processes
operate at low viscosity, and are amenable to close
15 control of process parameters such as pH, temperature and
dissolved oxygen. Moreover, sterile conditions are
readily preserved without resort to antibiotics.
The bioconversion process is exothermic, so
that heat should be removed, using a jacketed fermenter
20 or a cooling coil within the production fermenter.
Alternatively, the reaction broth may be circulated
through an external heat exchanger. Dissolved oxygen is
preferably maintained at a level of at least about 5%,
preferably at least about 10%, by volume, sufficient to
25 provide energy for the reaction and assure conversion of
the glucose to COZ and H20, by regulating the rate of air
introduced into the reactor in response to measurement of
oxygen potential in the broth. The pH is preferably
controlled at between about 4.5 and about 6.5.
30 In each of the alternative processes for 11-
hydroxylation of the substrate of Formula XIII,
productivity is limited by mass transfer from the solid
substrate to the aqueous phase, or the phase interface,
where reaction is understood to occur. As indicated
35 above, productivity is not significantly limited by mass
transfer rates so long as the particle mean particle size
CA 02550897 1997-12-11
61
of the substrate is reduced to less than about 300 ~, and
at least 75% by weight of the particles are smaller than
240 ~. However, productivity of these processes may be
further enhanced in certain alternative embodiments which
provide a substantial charge of canrenone or other
Formula xIII substrate to the production fermenter in an
organic solvent. According to one option, the substrate
is dissolved in a water-immiscible solvent and mixed with
the aqueous growth medium inoculum and a surfactant.
Useful water-immiscible solvents inlcude, for example,
DMF, DMSO, C6-C12 fatty acids, C6-C12 n-alkanes, vegetabla
oils, sorbitans, and aqueous surfactant solutions:
Agitation of this charge generates an emulsion reaction
system having an extended interfacial area for mass
transfer of substrate from the organic liquid phase to
the reaction sites.
A second option is to initially dissolve the
substrate in a water miscible solvent such as acetone,
methylethyl ketone, methanol, ethanol, or glycerol in a
concentration substantially greater than its solubility
in water. Hy preparing the initial substrate solution at
elevated temperature, solubility is increased, thereby
further increasing the amount of solution form substrate
introduced into the reactor and ultimately enhancing the
reactor payload. The warm substrate solution is charged
to the production fermentation reactor along with the
relatively cool aqueous charge comprising growth medium
and inoculum. When the substrate solution is mixed with
the aqueous medium, precipitation of the substrate
occurs. However, under conditions of substantial
supersaturation and moderately vigorous agitation,
nucleation is favored over crystal growth, and very fine
particles of high surface area are formed. The high
surface area promotes mass transfer between the liquid
phase and the solid substrate. Moreover, the equilibrium
concentration of substrate in the aqueous liquid phase is
CA 02550897 1997-12-11
62
also enhanced in the presence of a water-miscible
solvent. Accordingly, productivity is promoted.
Although the microorganism may not necessarily
tolerate a high concentration of organic solvent in the
aqueous phase, a concentration of ethanol, e.g., in the
range of about 3% to about 5% by weight, can be used to
advantage.
A third option is to solubilize the substrate
in an aqueous cyclodextrin solution. Illustrative
l0 cyclodextrins include hydroxypropyl-R-cyclodextrin and
methyl-~i-cyclodextrin. The molar ratio of
substrate:cyclodextrin can be about 1:0.5 to about 1:1.5,
more preferably about 1:0.8 to about 1:1. The
substrate:cyclodextrin mixture can then be added
aseptically to the bioconversion reactor.
lla-Hydroxycanrenone and other products of the
lla-hydroxylation process (Formulae VIII and VIIIA) are
novel compounds which may be isolated by filtering the
reaction medium and extracting the product from the
biomass collected on the filtration medium. Conventional
organic solvents, e.g., ethyl acetate, acetone, toluene,
chlorinated hydrocarbons, and methyl isobutyl ketone may
be used for the extraction. The product of Formula VITI
may then be recrystallized from an organic solvent of the
same type. The compounds of Formula VIII have
substantial value as intermediates for the preparation of
compounds of Formula I, and especially of Formula IA.
Preferably, the compounds of Formula VIII
correspond to Formula VIIIA in which -A-A- and -B-B- are
-CHZ-CH2-, R3 is hydrogen, lower alkyl or lower alkoxy,
and R8 and R9 together constitute the 20-spiroxane ring:
0
0
XXXIIi
CA 02550897 1997-12-11
63
Further in accordance with the process of
Scheme 1, the compound of Formula VIII is reacted under
alkaline conditions with a source of cyanide ion to
produce an enamine compound of Formula VII
R9
3
C
NH2 VII
wherein -A-A-, -B-B-, R3, R8 and R9 are as defined above.
Where the substrate corresponds to Formula VIIIA, the
product is of Formula VIIA
Y2
3 Y~
HO R HsC ~w( CH2) 2 C=X
iii
CHI B
i A Bi
A
I _CN
~C
NH2
VI IA
wherein -A-A-, -H-B-, R', Yl, YZ, and X are as defined in
Formula XIIIA. Preferably, R3 is hydrogen.
Cyanidation of the lla-hydroxyl substrate of
Formula VIII may be carried out by reacting it with a
cyanide ion source such as a ketone cyanohydrin, most
preferably acetone cyanohydrin, in~the presence of a base
and an alkali metal salt, most preferably LiCl.
Alternatively, cyanidation can be effected without a
cyanohydrin by using an alkali metal cyanide in the
presence of an acid.
CA 02550897 1997-12-11
64
In the ketone cyanohydrin process, the reaction
is conducted in solution, preferably using an aprotic
polar solvent such as dimethylformamide or dimethyl
sulfoxide: Formation of the enamine requires at least
two moles of cyanide ion source per mole of substrate,
and preferably a slight excess of the cyanide source is
used. The base is preferably a nitrogenous base such as
a dialkylamine, trialkylamine, alkanolamine, pyridine or
the like. However, inorganic bases such as alkali metal
carbonates or alkali metal hydroxides can also be used.
Preferably, the substrate of Formula VIII is initially
present in a proportion of between about 20 and about 50~
by weight and the base is present in a proportion of
between 0.5 to two equivalents per equivalent of
substrate. The temperature of the reaction is not
critical, but productivity is enhanced by operation at
elevated temperature. Thus, for example, where
triethylamine is used as the base, the reaction is
advantageously conducted in the range of about 80°C to
about 90°C. At such temperatures, the reaction proceeds
to completion in about 5 to about 20 hours. When
diisopropylethyl amine is used as the base and the
reaction is conducted at 105°C, the reaction is completed
at 8 hours. At the end of the reaction period, the
solvent is removed under vacuum and the residual oil
dissolved in water and neutralized to pH 7 with dilute
acid, preferably hydrochloric. The product precipitates
from this solution, and is thereafter washed with
distilled water and air dried. Liberated HCN may be
stripped with an inert gas and quenched in an alkaline
solution. The dried precipitate is taken up in
chloroform or other suitable solvent, then extracted with
concentrated acid, e.g., 6N HC1. The extract is
neutralized to pH 7 by addition of an inorganic base,
preferably an alkali metal hydroxide, and cooled to a
temperature in the range of 0°C. The resulting
CA 02550897 1997-12-11
precipitate is washed and dried, then recrystallized from
a suitable solvent, e.g., acetone, to produce a product
of Formula VII suitable for use in the next step of the
process.
5 Alternatively, the reaction may be conducted in
an aqueous solvent system comprising water-miscible
organic solvent such as methanol or in a biphasic system
comprising water and an organic solvent such as ethyl
acetate. In this alternative, product may be recovered
10 by. diluting the reaction solution with water, and
thereafter extracting the product using an organic
solvent such as methylene chloride or chloroform, and
then back extracting from the organic extract using
concentrated mineral acid, e.g., 2N HC1. See U.S. patent
15 3,200,113.
According to a still further alternative; the
reaction may be conducted in a water-miscible solvent
such as dimethylformamide, dimethylacetamide, N-methyl,
pyrolidone or dimethyl sulfoxide, after which the
20 reaction product solution is diluted with water and
rendered alkaline, e.g., by addition of an alkali metal
carbonate, then cooled to 0° to 10°C, thereby causing the
product to precipitate. Preferably, the system is
quenched with an alkali metal hypohalite or other reagent
25 effective to prevent evolution of cyanide. After
filtration and washing with water, the precipitated
product is suitable for use in the next step of the
process.
- According to a still further alternative, the
30 enamine product of Formula VII may be produced by
reaction of a substrate. of Formula VIII in the presence
of a proton source, with an excess.of alkali metal
cyanide, preferably NaCN, in an aqueous solvent
comprising an aprotic water-miscible polar solvent such
35 as dimethylformamide or dimethylacetamide. The proton
source is preferably a mineral acid or C1 to CS
CA 02550897 1997-12-11
66
carboxylic acid, sulfuric acid being particularly
preferred. Anomalously, no discrete proton source need
be added where the cyanidation reagent is commercial LiCN
in DMF.
A source of cyanide ion such as an alkali metal
salt is preferably charged to the reactor in a proportion
of between about 2.05 and about 5 molar equivalents per
equivalent of substrate. The mineral acid or other
proton source is believed to promote addition of HCN
across the 4,5 and 6,7 double bonds, and is preferably
present in a proportion of at least one mole equivalent
per mole equivalent substrate; but the reaction system
should remain basic by maintaining an excess of alkali
metal cyanide over acid present. Reaction is preferably
carried out at a temperature of at least about 75°C,
typically 60°C to 100°C, for a period of about 1 to about
8 hours, preferably about 1.5 to about 3 hours. At the
end of the reaction period, the reaction mixture is
cooled, preferably to about room temperature; and the
product enamine is precipitated by acidifying the
reaction mixture and mixing it with cold water,
preferably at about ice bath temperature. Acidification
is believed to close the 17-lactone, which tends to open
under the basic conditions prevailing in the cyanidation.
The reaction mixture is conveniently acidified using the
same acid that is present during the reaction, preferably
sulfuric acid. Water is preferably added in a proportion
of between about 10 and about 50 mole equivalents per
mole of product.
The compounds of Formula VII are novel
compounds and have substantial value as intermediates for
the preparation of compounds of Formula I, and especially
of Formula.IA. Preferably, the compounds of Formula VII
correspond to Formula VIIA in which -A-A- and -H-B- are
-CHz-CH2-, R3 is hydrogen, lower alkyl or lower alkoxy,
and Re and R9 together constitute the 20-spiroxane ring:
CA 02550897 1997-12-11
67
0
0
,gun XXXIII
Most preferably the compound of Formula VII is
5'R(5'a),7'/3-20'-Aminohexadecahydro-11'~B-hydroxy-
10'a,13'a-dimethyl-3',5-dioxospiro[furan-2(3H),17'a(5'H)-
[7, 4 ] metheno [4H] cyclopenta [a] phenanthrene] -5' -
carbonitrile.
In the conversion of the compound of Formula
VIII to the enamine of Formula VII, the 7-cyano
derivative of the compound of Formula VIII has been
observed by chromatography in the crude product. It is
hypothesized that the 7-cyano compound is an intermediate
in the conversion process. It is further hypothesized
that the 7-cyano intermediate itself reacts to form a
second intermediate, the 5,7-dicyano derivative of the
compound of Formula VIII, which in turn reacts to form
the enester. See, e.g., R. Christiansen et al., The
Reaction of Steroidal 4,6-Dien-3-Ones With Cyanide,
Steroids, Vol. 1, June 1963. These novel compounds
also have utility as chromatographic markers as well
as being synthetic intermediates. In a preferred
embodiment of this step of the overall Scheme d
synthesis process, these intermediates are 7a-cyano-
lla, 17-dyhydroxy-3-oxo-17a-pregn-4-ene-21-
dicarboxylic acid, y-Iactone, and 5~i, 7a-dicyano-
Ila, 17-dihydroxy-3-oxo-17a-pregnane-21-dicarboxylic
acid, y-lactone.
In the next step of the Scheme 1 synthesis, the
enamine of Formula VII is hydrolyzed to produce a
diketone compound of Formula VI
CA 02550897 1997-12-11
68
R3 p8
I v
s
i
s
,
~,
., ;
VI
where -A-A- , -H-e- ; R' , R° and R9 are as defined in
Formula XIII. Any aqueous organic or mineral acid can be
used for the hydrolysis. Hydrochloric acid is preferred.
To enhance productivity, a water-miscible organic
solvent., such as dimethylacetamide.or a lower alkanol, is
preferably used as a cosolvent. More preferably,
dimethylacetamide is the solvent. The acid should be
present in proportion of at least one equivalent per
equivalent of Formula VII substrate. In an aqueous
system, the enamine substrate VII can be substantially
converted to the diketone of Formula VI in a period of
about 5 hours at about 80°C. Operation at elevated
temperature increases productivity, but temperature is
not critical. Suitable temperatures are selected based
on the volatility of the solvent system and acid.
Preferably, the enamine substrate of Formula
VII corresponds to Formula VIIA
R3 Y2
Y~ I
HO~~~ H3C '~~~C CHZ) 2 C-X
t
CH3 B
B
A
I ~CN
~C ,
I
NHZ VI IA
CA 02550897 1997-12-11
69
and the diketone product corresponds to Formula VIA
R3 Y2
Y~
HO H3~ '~w CHz) ~ C-X
iiii
CH3 ~8
A
A~
I _CN
u' ~;
,:
fl
o VIA
in each of which -A-A-, -H-B-, R', Y1, Ya, and X are as
defined in Formula XIIIA. Preferably, R3 is hydrogen.
At the end of the reaction period, the solution
is cooled to between about 0° to 25°C to crystallize the
product. The product crystals may be recrystallized from
a suitable solvent such as isopropanol or methanol to
produce a product of Formula VI suitable for use in the
next step of the process; but recrystallization is
usually not necessary. The products of Formula VI are
novel compounds which have substantial value as
intermediates for the preparation of compounds of Formula
I, and especially of Formula IA. Preferably, the
compounds of Formula VI correspond to Formula VIA in
which -A-A- and -H-B- are -CHI-CHI-, R3 is hydrogen, lower
alkyl or lower alkoxy, and Re and R9 together constitute
the 20-spiroxane ring:
0
0
XXXIII
Most preferably, the compound of Formula Vi is
4'S(4'a),7'a-Hexadecahydro-11'a-hydroxy-10'~i,13'~i-
dimethyl-3',5,20'-trioxospiro[furan-2(3H),17'~i-
[4, 7] methano [17H] cyclopenta [a] phenanthrene] -5' R (2' H) -
carbonitrile.
CA 02550897 1997-12-11
In a particularly preferred embodiment of the
invention, the product enamine of Formula VII is produced
from the compound of Formula VIII in the manner described
above, and converted in situ to the diketone of Formula
VI. In this embodiment of the invention, a formula VIII
substrate is reacted with an excess of alkali metal
cyanide in an aqueous solvent containing a proton source,
or optionally an excess of ketone cyanohydrin in the
presence of a base and LiCl, as described hereinabove.
However, instead of cooling the reaction mixture,
acidifying, and adding water in proportions calculated to
cause precipitation of the enamine, substantial cooling
of the reaction mixture is preferably avoided. Water and
an acid, preferably a mineral acid such as sulfuric, are
I5 instead added to the mixture at the end of the
cyanidation reaction. The proportion of acid added is
sufficient to neutralize excess alkali metal cyanide,
which ordinarily requires introduction of at least one
molar equivalent acid per mole of Formula VIII substrate,
preferably between about 2 and about 5 mole equivalents
per equivalent substrate. However, the temperature is
maintained at high enough, and the dilution great enough,
so that substantial precipitation is avoided and
hydrolysis of the enamine to the diketone is allowed to
proceed in the liquid phase. Thus, the process proceeds
with minimum interruption and high productivity.
Hydrolysis is preferably conducted at a temperature of at
least 80°C, more preferably in the range of about 90°C to
about 100°C, far a period of typically about l to about
10 hours, more preferably about 2 to about 5 hours. Then
the reaction mixture is cooled, preferably to a
temperature of between about 0°C and about 15°C,
advantageously in an ice bath to about 5°C to about 10°C,
for precipitation of the product diketone of Formula VI.
The solid product may be recovered, as by filtration, and
impurities reduced by washing with water.
CA 02550897 1997-12-11
71
In the next step of the Scheme 1 synthesis, the
diketone compound of Formula VI is reacted with a metal
alkoxide to open up the ketone bridge between the 4 and 7
positions via cleavage of the bond between the carbonyl
group and the 4-carbon, form an a-oriented alkoxycarbonyl
substituent at the 7 position, and eliminate cyanide at
the 5-carbon. The product of this reaction is a
hydroxyester compound corresponding to Formula V
R3 RB
I \ R9
B
8
iiii R 1
V
where -A-A- , -B-B- , R' , Re and R9 are as def fined in
Formula XIII, and R1 is lower alkoxycarbonyl or
hydroxycarbonyl. The metal alkoxide used in the reaction
corresponds to the formula R1°OM where M is alkali metal
and Rl°O- corresponds to the alkoxy substituent of Rl.
Yields of this reaction are most satisfactory when the
metal alkoxide is potassium methoxide or sodium
methoxide, but other lower alkoxides can be used. A
potassium alkoxide is particularly preferred.
Phenoxides, other aryloxides may also be used, as well as
arylsulfides. The reaction is conveniently carried out
in the presence of an alcohol corresponding to the
formula R1°OH where R1° is as defined above. Other
conventional solvents may be used. Preferably, the
Formula VI substrate is present in a~proportion of
between about 2°s and about 12% by weight, more preferably
at least about 6% by weight. Preferably, R1°OM is present
in a proportion of between about 0.5 and about ~ moles
per mole of substrate, more preferably between about..l
and about 2 moles per mole of substrate, and still more
preferably about 1.6 mole per mole of substrate.
CA 02550897 1997-12-11
72
Temperature is not critical but elevated temperature
enhances productivity. Reaction time is typically
between about 4 and about 24 hours, preferably about 4 to
16 hours. Conveniently, the reaction is carried out at
atmospheric reflux temperature depending on the solvent
used.
The time required for the reaction to reach
equilibrium is affected by the amount of alkoxide that is
added to the reaction mixture and the manner in which the
alkoxide is added. The alkoxide may be added in a single
portion or in multiple portions or it may be added
continuously: When alkoxide is added in multiple
portions, it is preferable that about 1.6 equivalents of
potassium methoxide be added in two steps. In this two-
step addition, 1 equivalent of potassium methoxide is
initially added to the reaction mixture followed by the
addition of 0.6 equivalents of potassium methoxide about
90 minutes later. This two-step addition shortens the
time to reach equilibrium relative to a single portion
addition of 1.6 equivalents of potassium methoxide.
Because the equilibrium is more favorable for
the production of the hydroxyester at low concentrations
of the diketone, the reaction is preferably run at rather
high dilution, e.g., as high as 40:1 for reaction with
sodium methoxide. It has been found that significantly
higher productivity can be realized by use. of potassium
methoxide rather than sodium methoxide, because a
dilution in the range of about 20:1 is generally
sufficient to minimize the extent of reverse cyanidation
where potassium methoxide is the reagent.
In accordance with the invention, it has been
further discovered that the reverse cyanidation reaction
may be inhibited by taking appropriate chemical or
physical measures to remove by-product cyanide ion from
the reaction zone. Thus, in a further embodiment of the
invention, the reaction of the diketone with alkali metal
CA 02550897 1997-12-11
73
alkoxide may be carried out in the presence of a
precipitating agent for cyanide ion such as, for example,
a salt comprising a cation which forms an insoluble
cyanide compound. Such salts may, for example, include
zinc iodide, ferric sulfate, or essentially any halide,
sulfate or other salt of an alkaline earth or transition
metal that is more soluble than the corresponding
cyanide. If zinc iodide is present in proportions in the
range of about one equivalent per equivalent diketone
l0 substrate, it has been observed that the productivity of
the reaction is increased substantially as compared to
the process as conducted in the absence of an alkali
metal halide.
Even where a precipitating agent is used for
removal of cyanide ion, it remains preferable to run at
fairly high dilution, but by use of a precipitating agent
the solvent to diketone substrate molar ratio may be
reduced significantly compared to reactions in the
absence of such agent. Recovery of the hydroxyester of
2o Formula V can be carried out according to either the
extractive or non-extractive procedures described below.
The equilibrium of the reaction also can be
controlled to favor the production of the hydroxyester of
Formula V by removing this hydroxyester from the reaction
mixture after it is synthesized. The removal of the
hydroxyester can proceed either stepwise or continuously
through means such as filtration. The removal of the
hydroxyester can be used to control the equilibrium
either alone or in combination vuith the chemical or
physical removal of cyanide from the reaction mixture.
Heating of the resulting filtrate then drives the
reaction equilibrium to favor of the conversion of the
remaining diketone of Formula VI to the hydroxyester of
V.
In the conversion of the diketone of Formula VI
to the hydroxyester of Formula V the 5-cyano hydroxyester
CA 02550897 1997-12-11
74
has been observed in the crude product in small amounts,
typically less than about 5% by weight. It is
hypothesized that the 5-cyano hydroxyester is an
equilibrium intermediate between the diketone of Formula
VI and the hydroxyester of Formula V. It is further
hypothesized that this equilibrium intermediate is formed
from the diketone through methoxide attack on the 5,7-oxo
group and protonation of the enolate, and from the
hydroxyester through a Michael addition of by-product
cyanide ion to the 3-keto-D°'S function of the
hydroxyester.
In addition, the 5-cyano-7-acid and the 17-
alkoxide of the hydroxyester of Formula V have been
observed by chromatography in the crude product. It is
hypothesized that the 5-cyano hydroxyester intermediate
reacts with by-product cyanide ion (present as a result
of the decyanation which introduces the D''S double bond)
to produce the 5-cyano-7-acid. It is hypothesized that
the action of the cyanide ion dealkylates the 7-ester
group of the 5-cyano hydroxyester to yield the 5-cyano-7-
acid and the corresponding alkylnitrile.
It is further hypothesized that transient
intermediate 17-alkoxide is formed from the attack of the
methoxide on the 17-spirolactone of the hydroxyester (or
a preceding intermediate which subsequently converts into
the hydroxyester). The 17-alkoxide readily converts into
the hydroxyester upon treatment with an acid. Therefore,
it generally is not observed in the product matrix.
The 5-cyano hydroxyester, the 5-cyano-7-acid,
and the 17-alkoxide are novel compounds which are useful
as chromatographic markers and as intermediates in the
preparation, of the hydroxyester. They can be isolated
from the crude product of this step of the Scheme 1
synthesis. Alternatively, they can be synthesized
directly for use as markers or intermediates. The 5-
cyano hydroxyester can be synthesized by reacting a
CA 02550897 1997-12-11
solution of the isolated diketone of Formula VI with a
base, such as an alkoxide or an amine, and isolating the
resulting precipitate. The compound prepared preferably
is 7-methyl hydrogen 5(3-cyano-11a,17-dihydroxy-3-oxo-17a-
5 pregnane-7a,21-dicarboxylate, 'y-lactone.
The 5-cyano-7-carboxylic acid can be
synthesized directly by reacting the diketone of Formula
VI with a weak aqueous base, such as sodium acetate or
sodium bicarbonate, and isolating the resulting
10 precipitate. The compound prepared preferably is 5-,5-
cyano-11-a,17-dihydroxy-3-oxo-17a-pregnane-7a,21-
dicarboxylic acid, 7-lactone.
The 17-alkoxide can be synthesized directly by
reacting a solution of the hydroxyester of Formula V with
15 an alkoxide to yield a mixture of the 17-alkoxide and the
corresponding hydroxyester. The compound prepared
preferably is dimethyl l1a,17-dihydroxy-3-oxo-17a-pregn-
4-ene-7x,21-dicarboxylate, 'y-lactone.
Preferably, the diketone substrate of Formula
20 VI corresponds to Formula VIA
R3 Yz
1
H0, H3C Y ~w~ CH2) z C-X
CH3 B
A
A~
I _CN
fl
VIA
and the hydroxyester product corresponds to Formula VA
CA 02550897 1997-12-11
76
R3 Y2
Y~
HO~~~ H3C '~~~C CHZ] ~ C-X
i
CH, ~B
A~
~iiyR ~
VA
in each of which -A-A-, -H-B-, R', Y1, YZ, and X are as
defined in Formula XIIIA and R1 is as defined in Formula
V. Preferably, R3 is hydrogen.
The products of Formula V are novel compounds
which have substantial value as intermediates for the
preparation of compounds of Formula I, and especially of
Formula IA. Preferably, the compounds of Formula V
correspond to Formula VA in which -A-A- and -B-B- are
-CH2-CHZ-, R3 is hydrogen, lower alkyl or lower alkoxy,
and Re and R9 together constitute the 20-spiroxane ring:
0
0
,n XXXIII
Most preferably, the compound of Formula V is Methyl
Hydrogen l1a,17a-Dihydroxy-3-oxopregn-4-ene-7a,21-
dicarboxylate, y-Lactone.
The compound of Formula V may be isolated by
filtration or by acidifying the reaction solution, e.g.,
with a mineral acid such as aqueous HC1 or sulfuric acid,
cooling to ambient temperature, and extracting the
product with an organic solvent such as methylene
chloride or ethyl acetate. The extract is washed with an
aqueous alkaline wash solution, dried and filtered, after
which the solvent is removed. Alternatively, the
reaction solution containing the product of Formula V may
be quenched with concentrated acid. The product solution
is concentrated, cooled to between about 0° to 25°C and
the product solid is isolated by filtration.
CA 02550897 1997-12-11
77
In a preferred embodiment, methanol and HCN are
removed by distillation after the conclusion of the
reaction period, with mineral acid (such as hydrochloric
acid or sulfuric acid) being added before the
distillation and water being added after the
distillation. The mineral acid can be added in a single
step, in multiple steps or continuously. In a preferred
embodiment, mineral acid is continuously added over a
period of about 10 to about 40 minutes, more preferably
about 15 to about 30 minutes. Likewise, water can be
added to the still bottoms in a single step, in multiple
steps or continuously. In a preferred embodiment, the
concentrated reaction mixture is~cooled from reflux
temperature prior to addition of water. Preferably, the
mixture is cooled to a temperature between about 50°C to
about 70°C, preferably between about 60°C to about 70°C,
and more preferably about 65°C, prior to addition of the
water. Water is then added, preferably continuously over
a period of about 15 minutes to about 3 hours, and more
preferably over about 60 minutes to about 90 minutes,
while maintaining the temperature approximately constant.
Product of Formula V begins to crystallize from the still
bottoms as the water addition proceeds. After the water
has been added to the mixture, the diluted reaction
mixture is maintained at about the same temperature for
about 1 hour and then cooled to about 15°C over an
additional period of about 4 to about 5 hours. The
mixture is maintained at about 15°C for a period of about
1 to 2 hours. A longer holding period at 15°C increases
the yield of the cyanoester in the mixture. This mode of
recovery provides a high quality crystalline product
without extraction operations.
According to another preferred mode of recovery
of the product of Formula V, methanol and HCN are removed
by distillation after the conclusion of the reaction
period, with water and acid being added before or during
CA 02550897 1997-12-11
7a
the distillation. Addition of water before the
distillation simplifies operations, but progressive
addition during the distillation allows the volume in the
still to be maintained substantially constant. Product
of Formula V crystallizes from the still bottoms as the
distillation proceeds. This mode of recovery provides a
high quality crystalline product without extraction
operations.
In accordance with yet a further alternative,
the reaction solution containing the product of Formula V
may be quenched with mineral acid, e.g., 4N HC1; after
which the solvent is removed by distillation. Removal of
the solvent is also effective for removing residual HCN
from the reaction product. It has been found that
multiple solvent extractions for purification of the
compound of Formula V are not necessary where the
compound of Formula V serves as an intermediate in a
process for the preparation of epoxymexrenone, as
described herein. In fact, such extractions can often be
entirely eliminated. Where solvent extraction is used
for product purification, it is desirable to supplement
the solvent washes with brine and caustic washes. But
where the solvent extractions are eliminated, the brine
and caustic washes are too. Eliminating the extractions
and washes significantly enhances the productivity of the
process, without sacrificing yield or product quality,
and also eliminates the need for drying of the washed
solution with a dessicant such as sodium sulfate.
The crude lla-hydroxy-7a-alkoxycarbonyl product
is taken up again in the solvent for the next reaction
step of the process, which is the conversion of the 11-
hydroxy group to a leaving group at the 11 position
thereby producing a compound of Formula IV:
CA 02550897 1997-12-11
79
R~ Re
1 v R°
B
i
B
~~,,R~
IV
where -A-A- , R3 , -B-B- , RB and R9 are as def fined in
Formula XIII, R1 is as defined in Formula V, and R2 is
lower arylsulfonyloxy, alkylsulfonyloxy, acyloxy or
halide. Preferably, the lla-hydroxy is esterified by
reaction with a lower alkylsulfonyl halide, an acyl
halide or an acid anhydride which is added to the
solution containing the intermediate product of Formula
V. Lower acid anhdyrides such as acetic anhydride and
trihalogenated acid anhydrides such as trifluoroacetic
anhydride can be used to prepare suitable acyloxy leaving
groups. Lower alkylsulfonyl halides, and especially
methanesulfonyl chloride, however, are preferred.
Alternatively, the 11-a hydroxy group could be converted
to a halide by reaction of a suitable reagent such as
thionyl bromide, thionyl chloride, sulfuryl chloride or
oxalyl chloride. Other reagents for forming lla-sulfonic
acid esters include tosyl chloride, benzenesulfonyl
chloride and trifluoromethanesulfonic anhydride. The
reaction is conducted in a solvent containing a hydrogen
halide scavenger such as triethylamine or pyridine.
Inorganic bases such as potassium carbonate or sodium
carbonate can also be used. The initial concentration of
the hydroxyester of Formula V is preferably between about
5% and about 50% by weight. The esterification reagent
is preferably present in slight excess. Methylene
chloride is a particularly suitable.solvent for the
reaction, but other solvents such as dichloroethane,
pyridine, chloroform, methyl ethyl ketone,
dimethoxyethane, methyl isobutyl ketone, acetone, other
ketones, ethers, acetonitrile, toluene, and
CA 02550897 1997-12-11
tetrahydrofuran can also be employed. The reaction
temperature is governed primarily by the volatility of
the solvent: In methylene chloride, the reaction
temperature is preferably in the range of between about
-10°C and about 10°C.
Preferably, the hydroxyester substrate of
Formula V corresponds to Formula VA
HO/ H3C Y \\\'C CHZ) 2 C-X
1 I
//
CH3 B
A /
Ai B
p / ///i R ~
VA
and the.product corresponds to Formula IVA
Y2
Y1 I
R? ~H3~ ~.v~~CH2)2 C-X
CH3 B
i A B/
A
/ /,/~ R 1
IVA
in each of which -A-A- , -B-B- , R' , Y1, YZ , and X are as
defined in Formula XIIIA, R1 is lower alkoxycarbonyl or
hydroxycarbonyl, and RZ is as defined in Formula IV.
Preferably, R3 is hydrogen.
The products of Formula IV are novel compounds
which have substantial value as intermediates for the
preparation of compounds of Formula I, and especially'of
Formula IA. Preferably, the compounds of Formula IVA
correspond to Formula VA in which -A-A- and -B-H- are -
CHz-CHI-, R3 is hydrogen, lower alkyl or lower alkoxy, and
Re and R9 together constitute the 20-spiroxane ring:
CA 02550897 1997-12-11
81 .
0
0
XXXIII
Most preferably, the compound of Formula IV is l~9ethyl
Hydrogen 17a-Hydroxy-11a-(methylsulfonyl)oxy-3-oxopregn-
4-ene-7x,21-dicarboxylate, 'y-Lactone. Where an acyloxy
leaving group is desired, the compound of Formula IV is
preferably 7-methyl hydrogen 17-hydroxy-3-oxo-lla-(2;2,2-
trifluoro-1-oxoethoxy)-17a-pregn-4-ene-7a,21-
dicarboxylate, 'y-lactone; or 7-methyl 11a-(acetyloxy)-17-
hydroxy-3-oxo-17a-pregn-4-ene-7a,21-dicarboxylate, y-
lactone.
If desired, the compound of Formula IV may be
isolated by removal of the solvent. Preferably, the
reaction solution is first washed with an aqueous
alkaline wash solution,~e.g., 0.5-2N NaOH, followed by an
acid wash, e.g., 0.5-2N HC1. After removal of the
reaction solvent, the product is recrystallized, e.g., by
taking the product up in methylene chloride and then
adding another solvent such as ethyl ether which lowers
the solubility of the product of Formula IV, causing it
to precipitate in crystalline form.
In the recovery of the product of Formula IV,
or in preparation of the reaction solution for conversion
of the Formula IV intermediate to the intermediate of
Formula II as is further described hereinbelow, all
extractians and/or washing steps may be dispensed with if
the solution is instead treated with ion exchange resins
for removal of acidic and basic impurities. The solution
is treated first with an anion exchange resin, then with
a cation exchange resin. Alternatively, the reaction
solution may first be treated with inorganic adsorbents
such as basic alumina or basic silica, followed by a
dilute acid wash. Basic silica or basic alumina may
typically be mixed with the reaction solution in a
CA 02550897 1997-12-11
82
proportion of between about 5 and about 50 g per kg of
product, preferably between about 15 and about 20 g per
kg product. Whether ion exchange resins or inorganic
adsorbents are used, the treatment can be carried out by
simply slurrying the resin or inorganic adsorbent with
the reaction solution under agitation at ambient
temperature, then removing the resin or inorganic
adsorbent by filtration.
In an alternative and preferred embodiment of
the invention, the product compound of Formula IV is
recovered in crude form as a concentrated solution by
removal of a portion of the solvent. This concentrated
solution is used directly in the following step of the
process, which is removal of the llcx-leaving group from
the compound of Formula IV, thereby producing an enester
of Formula II:
R3 R8
I
'8
A
A~ 8
0 / iiyR ~
II
where -A-A-, -B-B-, R', RB and R9 are as defined in
Formula XIII, and R' is as defined in Formula V. For
purposes of this reaction, the R2 substituent of the
compound of Formula IV may be any leaving group the
abstraction of which is effective for generating a double
bond between the 9- and 11-carbons. Preferably, the.
leaving group is a lower alkylsulfonyloxy or acyloxy
substituent which is removed by reaction with an acid and
an alkali metal salt. Mineral acids can be used, but
lower alkanoic acids are preferred. Advantageously, the
reagent for the reaction further includes an alkali metal
salt of the alkanoic acid utilized. It is particularly
preferred that the leaving group comprise mesyloxy and
CA 02550897 1997-12-11
83
the reagent for the reaction comprise formic acid or
acetic acid and an alkali metal salt of one of these
acids or another lower alkanoic acid. Where the leaving
group is mesyloxy and the removal reagent is either
acetic acid and sodium acetate or formic acid and
potassium formate, a relatively high ratio of 9;17,-olefin
to 11,12-olefin is observed. If tree water is present
during removal of the leaving group, impurities tend to
be formed, particularly a 7,9-lactone
R9
where -A-A- , R' , -H-B- , RB and R9 are as defined in
Formula XIII, which is difficult to remove from the final
product. Hence, acetic anhydride or other drying agent
is used to remove the water present in formic acid. The
free water content of the reaction mixture before
reaction should be maintained at a level below about
0.5%~, preferably below about 0.1% by weight, as measured
by Karl Fischer analysis for water, based on total
reaction solution. Although it is preferred that the
reaction mixture be kept as dry as practicable,
satisfactory results have been realized with 0.3% by
weight water. Preferably, the reaction charge mixture
contains between about 4% and about 50% by weight of the
substrate of Formula IV in the alkanoic acid. Between
about 4% and about 20% by weight of the alkali metal salt
of the acid is preferably included. Where acetic
anhydride is used as the drying agent, it is preferably
present in a proportion of between about 0.05 moles and
about 0.2 moles per mole of alkanoic acid,
3
R "e
CA 02550897 1997-12-11
84
It has been found that proportions of by-
product 7,9-lactone and 11,12-olefin in the reaction
mixture is relatively low where the elimination reagent
comprises a combination of trifluoroacetic acid,
trifluoroacetic anhydride and potassium acetate as the
reagent for elimination of;the leaving group and
formation of the enester (9,11-olefin). Trifluoroacetic
anhydride serves as the drying agent, and should be
present in a proportion of at least about 3% by' weight,
more preferably at least about 15% by weight, most
preferably about 20% by weight, based on the
~trifluoroacetic acid eliminating reagent..
In addition to the 7,9-lactone, other
impurities and by-products which are useful as synthetic
intermediates and chromatographic markers have been
observed in this step of the Scheme 1 synthesis. The
novel 4,9,13-triene of the enester of Formula II' (for
example, 7-methyl hydrogen 17-methyl-3-oxo-18-norpregna-
4,9(11),13-triene-7x,21-dicarboxylate) has been isolated
chromatographically from the product solution. The
amount of this compound produced appears to increase with
an increase in reaction time for this step of the
synthesis. It is hypothesized that the compound is
formed when the lactone is protonated and the resulting
C17 carbonium ion facilitates the migration of the
angular methyl group from the C13 position.
Deprotonation of this intermediate yields the 4,9,13-
triene.
The novel 5-cyano-all,m of the enester of
Formula II (for example, 7-methyl hydrogen 5~3-cyano-17-
hydroxy-3-oxo-17a-pregn-11-ene-7x,21-dicarboxylate, 'y-
lactone) and the novel 5-cyano of the enester of Formula
II (for example. 7-methyl hydrogen 5-cyano-17-hydroxy-3-
oxo-17a-pregn-11-ene-7x,21-dicarboxylate, y-lactone) also
have been isolated chromatographically from the crude
product. It is hypothesized that these compounds are
CA 02550897 1997-12-11
formed via dehydration of the residual 5-cyano-?-acid and
5-cyano hydroxyester, respectively, which are present in
the crude product solution as a result of the third step
of the Scheme 1 synthesis.
5 The novel C17 epimer of the enester of Formula
II (for example, 7-methyl hydrogen 1?-hydroxy-3-oxo-17a-
pregna-4,9(11)-diene-7,21-dicarboxylate, ~y-lactone) also
has been isolated chromatographically from the crude
product. It is hypothesized that the acidic conditions
10 of the elimination reaction can result in racemization of
the C17 chiral center to yield the 17-epimer of the
enester. The 17-epimer can be synthesized directly by
reacting a compound of Formula IV with a solution of
potassium formate, formic acid and acetic anhydride and
15 isolating the 17-epimer.
Although not observed as an impurity in the
crude product solution, the 11-ketone of the hydroxyester
of formula V can be prepared by oxidizing the 11-hydroxy
of the corresponding hydroxyester with a suitable
20 oxidizing agent such as a Jones Reagent. The ll-ketone
prepared preferably is 7-methyl hydrogen 17-hydroxy-3,11-
dioxo-17a-pregna-4-ene-7x,21-dicarboxylate, 'y-lactone.
Alternatively, the lla-leaving groups from the
compound of Formula IV, may be eliminated to produce an
25 enester of Formula II by heating a solution of Formula IV
in an organic solvent such as DMSO, DMF or DMA.
Further in accordance with the invention, the
compound of Formula IV is reacted initially with an
alkenyl alkanoate such as isopropenyl acetate in the
30 presence of an acid such as toluene sulfonic acid or an
anhydrous mineral acid such as sulfuric acid to form the
3-enol ester:
CA 02550897 1997-12-11
86
Ra Ra
R2
B
A /
B
Ac O \ \ ~~/~R ~
Iv(z)
of the compound of Formula IV. Alternatively, the 3-enol
ester can be formed by treatment of the compound of
Formula IV with an acid anhydride and base such as acetic
acid and sodium acetate. Further alternatives include
treatment of the compound of Formula IV with ketene in
the presence of an acid to produce the compound of
Formula IV(Z). The intermediate of Formula IV(Z) is
thereafter reacted with an alkali metal formate or
acetate in the presence of formic or acetic acid to
produce the ~9m1 enol acetate of Formula IV (Y)
Rz R
~ R~
.B
AAA
A c O \ \ ~~~~ R ~
IV (Y)
which can then be converted to the enester of Formula II
in an organic solvent; preferably an alcohol such as
methanol, by either thermal decomposition of the enoi
acetate or reaction thereof with an alkali metal
alkoxide. The elimination reaction is highly selective
to the enester of Formula II in preference to the 11,12-
olefin and 7,9-lactone, and this selectivity is preserved
through conversion of the enol acetate to the enone.
Preferably, the substrate of Formula IV
corresponds to Formula IVA
CA 02550897 1997-12-11
87
R3 YZ
Y~ _
Rv ~H3~ w~~~CHZ~2 C-X
CH3 B
B
~~~i~p 1
IvA
and the enester product corresponds to Formula IIA
H3C Y2
3 Y1
1 ~ ~.w~CH2~2 C-X
CH3 ~ ~B
A
IIA
in each of which -A-A-, -B-H-, R3, Y1, Y~, and X are as
defined in Formula XIIIA, and Rl is as defined in Formula
V. Preferably, R, is hydrogen.
If desired, the compound of Formula II may be
isolated by removing the solvent, taking up the solid
product in cold water, and extracting with an organic
solvent, such as ethyl acetate. After appropriate
washing and drying steps, the product is recovered by
removing the extraction solvent. The enester is then
dissolved in a solvent appropriate for the conversion to
the product of Formula I. Alternatively, the enester can
be isolated by adding water to the concentrated product
solution and filtering the solid product, thereby
preferentially removing the 7,9-lactone. Conversion of
the substrate of Formula II to the product of Formula IA
may be conducted in the manner described in U.S. patent
4,559,332, or more preferably by the novel reaction
using a haloacetamide promoter as described below.
In another embodiment of the invention, the
hydroxyester of Formula V may be converted to the enester
CA 02550897 1997-12-11
88
of Formula II without isolation of the intermediate
compound of Formula IV. In this method, the hydroxyester
is taken up in an organic solvent, such as methylene
chloride; and either an acylating agent, e.g.,
methanesulfonyl chloride, or halogenating reagent; e.g.,.
sulfuryl chloride, is added to the solution. The mixture
is agitated and, where halogenation is involved, an HC1
scavenger such as imidazole is added. This reaction is
highly exothermic, and should therefore be conducted at a
controlled rate with full cooling. After the base
addition, the resulting mixture is warmed to moderate
temperature, e.9., about 0°C to room temperature or
slightly above, and reacted for a period of typically
about l to about 4 hours. After reaction is complete,
the solvent is stripped, preferably under high vacuum
(e. g., about 24° to about 28" Hg) conditions at about
-l0° to about +15°C, more preferably about 0° to about
5°C, to concentrate the solution and remove excess base.
The substrate is then redissolved in an organic solvent,
preferably a halogenated solvent such as methylene
chloride for conversion to the enester.
The leaving group elimination reagent is
preferably prepared by mixing an organic acid, an organic
acid salt and a drying agent, preferably formic acid,
alkali metal formate and acetic anhydride, respectively,
in a dry reactor. Addition of acetic anhydride is
exothermic and results in release of C0, so the addition
rate must be controlled accordingly. To promote the
removal of water, the temperature of this reaction is
preferably maintained in the range of about 60° to about
90°C, most preferably about 65° to about 75°C. This
reagent is then added to the product solution of the
compound of Formula IV to effect the elimination
reaction. After about 4 to about 8 hours, the reaction
mixture is preferably heated to a temperature of at least
about 85°C, but preferably not above about 95°C until all
CA 02550897 1997-12-11
89
volatile distillate has been removed, and then for an
additional period to complete the reaction , typically
about 1 to about 4 hours. The reaction mixture is
cooled, and after recovery by standard extraction
S techniques, the enester may be recovered as desired by
evaporating the solvent.
It has further been found that the enester of
Formula II may be recovered from the reaction solution by
an alternative procedure which avoids the need for
extraction steps following the elimination reaction,
thereby providing savings in cost, improvement in yield
and/or improvement in productivity. In this process, the
enester product is precipitated by dilution of the
reaction mixture with water after removal of formic acid.
The product is then isolated by filtration. No
extractions are required.
According to a further alternative for
conversion of the hydroxyester of Formula V to the
enester of Formula II without isolation of the compound
of Formula IV, the lla-hydroxy group of the Formula V
hydroxyester is replaced by halogen, and the Formula II
enester is then formed'in situ by thermal
dehydrohalogenation. Replacement of the hydroxy group by
halogen is effected by reaction with sulfuryl halide,
preferably sulfuryl chloride, in the cold in the presence
of a hydrogen halide scavenger such as imidazole. The
hydroxyester is dissolved in a solvent such as
tetrahydrofuran and cooled to about 0°C to about -70°C.
The sulfuryl halide is added and the reaction mixture is
warmed to moderate temperature, e.g., room temperature,
for a time sufficient to complete the elimination
reaction, typically about 1 to about 4 hours. The
process of this embodiment not only combines two steps
into one, but eliminates the use of: a halogenated
reaction solvent; an acid (such as acetic acid); and a
drying reagent (such as acetic anhydride or sodium
CA 02550897 1997-12-11
sulfate). Moreover, the reaction does not require
refluxing conditions, and avoids the generation of by-
product CO which results when acetic acid is used as a
drying reagent.
5 In accordance with a particularly preferred
embodiment of the invention, the diketone compound of
Formula VI can be converted to epoxymexrenone or other
compound of Formula I without isolating any intermediate
in purified form. In accordance with this preferred
10 process, the reaction solution containing the
hydroxyester is quenched with a strong acid solution,
cooled to ambient temperature and then extracted with an
appropriate extraction solvent. Advantageously, an
aqueous solution of inorganic salt, e.g., about 10~ by
15 weight saline solution, is added to the reaction mixture
prior to the extraction. The extract is washed and dried
by azeotropic distillation for removal of the methanol
solvent remaining from the ketone cleavage reaction:
The resulting concentrated solution containing
20 between about 5~ and about 50% by weight compound of
Formula V is then contacted in the cold with an acylating
or alkylsulfonylating reagent to form the sulfonic ester
or dicarboxylic acid ester. After the alkylsulfonation
or carboxylation reaction is complete, the reaction
25 solution is passed over an acidic and then a basic
exchange resin column for the removal of basic and acidic
impurities. After each pass, the column is washed with
an appropriate solvent, e.g., methylene chloride, for the
recovery of residual sulfonic or dicarboxylic ester
30 therefrom. The combined eluate and wash fractions are
combined and reduced, preferably under vacuum, to produce
a concentrated solution containing the sulfonic ester or
dicarboxylic ester of Formula IV. This concentrated
solution is then contacted with a dry reagent comprising
35 an agent effect for removal of the lla-ester leaving
group and abstraction of hydrogen to form a 9,11 double
CA 02550897 1997-12-11
91
bond. Preferably, the reagent for removal of the leaving
group comprises the formic acid/alkali metal
formate/acetic anhydride dry reagent solution described
above. After reaction is complete, the reaction mixture
is cooled and formic acid and/or other volatile
components are removed under vacuum. The residue is
cooled to ambient temperature, subjected to appropriate
washing steps,, and then dried to give a concentrated
solution containing the enester of Formula II. This
enester may then be converted to epoxymexrenone or other
compound of Formula I using the method described herein,
or in U.S. patent 4,559,332.
In an especially preferred embodiment of the
invention, the solvent is removed from the reaction
solution under vacuum, and the product of Formula IV is
partitioned between water and an appropriate organic
solvent, e.g., ethyl acetate. The aqueous layer. is then
back extracted with the organic solvent, and the back
extract washed with an alkaline solution, preferably a
solution of an alkali metal hydroxide containing an
alkali metal halide. The organic phase is concentrated,
preferably under vacuum, to yield the enester product of
Formula II. The product of Formula II may then be taken
up in an organic solvent, e.g., methylene chloride, and
further reacted in the manner described in the '332
patent to produce the product of Formula I.
Where trihaloacetonitrile is used in the
epoxidation reaction, it has been found that the
selection of solvent is important, with halogenated
solvents being highly preferred, and methylene chloride
being especially preferred. Solvents such as
dichloroethane and chlorobenzene give reasonably
satisfactory yields, but yields are generally better in a
methylene chloride reaction medium. Solvents such as
acetonitrile and ethyl acetate generally give poor
CA 02550897 1997-12-11
_ 92
yields, while reaction in solvents such as methanol or
water/tetrahydrofuran give little of the desired product.
Further in accordance with the present
invention, it has been discovered that numerous
improvements in the synthesis of epoxymexrenone can be
realized by use of a trihaloacetamide rather than a
trihaloacetonitrile as a peroxide activator for the
epoxidation reaction. In accordance with a particularly
preferred process, the epoxidation is carried out by
reaction of the substrate of Formula IIA with hydrogen
peroxide in the presence of trichloroacetamide and an
appropriate buffer. Preferably, the reaction is
conducted in a pH in the range of about 3 to about 7,
most preferably between about 5 and about 7. However,
despite these considerations, successful reaction has
been realized outside the preferred pH ranges.
Especially favorable results are obtained with
a buffer comprising dipotassium hydrogen phosphate,
and/or with a buffer comprising a combination of
dipotassium hydrogenphosphate and potassium dihydrogen
phosphate in relative proportions of between about 1:4
and about 2:1, most preferably in the range of about 2:3.
Borate buffers can also be used, but generally give
slower conversions than dipotassium phosphate or
KZHP04/KHzP04 mixtures . Whatever the makeup of the
buffer, it should provide a pH in the range indicated
above. Aside from the overall composition of the buffer
or the precise pH it may impart, it has been observed
that the reaction proceeds much more effectively if at
least a portion of the buffer is comprised of dibasic
hydrogenphosphate ion. It is believed that this ion may
participate essentially as a homogeneous catalyst in the
formation of an adduct or complex comprising the promoter
and hydroperoxide ion, the generation of which may in
turn be essential to the overall epoxidation reaction
mechanism. Thus, the quantitative requirement for
CA 02550897 1997-12-11
93
dibasic hydrogenphosphate (preferably from K=HPO,) may be
only a small catalytic concentration. Generally, it is
preferred that KZHPO, be present in a proportion of at
least about 0.1 equivalents, e.g., between about 0:1 and
about o.3 equivalents, per equivalent substrate.
The reaction is carried out in a suitable
solvent, preferably methylene chloride, but alternatively
other halogenated solvents such as chlorobenzene or
dichloroethane can be used. Toluene and mixtures of
toluene and acetonitrile have also been found
satisfactory. Without committing to a particular theory,
it is posited that the reaction proceeds most effectively
in a two phase system in which a hydroperoxide
intermediate is formed and distributes to the organic
phase of low water content, and reacts with the substrate
in the organic phase. Thus the preferred solvents are
those in which water solubility is low. Effective
recovery from toluene is promoted by inclusion of another
solvent such as acetonitrile.
In the conversion of substrates of Formula II
to products of Formula I, toluene provides a process
advantage since the substrates are freely soluble in
toluene and the products are not. Thus, the product
precipitates during the reaction when conversions reach
the 40-50% range, producing a three phase mixture from
which the product can be conveniently separated by
filtration. Methanol, ethyl acetate, acetonitrile alone,
THF and THF/water have not proved to be as effective as
the halogenated solvents or toluene in carrying out the
conversion of this step of the process.
While trichloroacetamide is a highly preferred
reagent, other trihaloacetamides such as
trifluoroacetamide and chlorodifluoroacetamide can also
be used. Trihalomethylbenzamide, and other compounds
having an arylene, alkenyl or alkynyl moiety (or other
group which allows the transfer of the electron
CA 02550897 1997-12-11
94
withdrawing effect of the electron withdrawing group to
the amide carbonyl) between the electron withdrawing
trihalomethyl group and the carbonyl of the amide, may
also be useful. Heptafluorobutyramides may also be used,
but with less favorable results. Generically, the
peroxide activator may correspond to the formula:
R°C ( O ) NH2
where R° is a group having an electron withdrawing
strength (as measured by sigma constant) at least as high
as that of the monochloromethyl group. The electron
withdrawing group preferably is attached directly to the
amide carbonyl for maximum effectiveness. More
particularly, the peroxide activator may correspond to
the formula:
x' o
Z I p II
X -C-R -C-N112
Ia
I5 x
where Rp is a group which allows the transfer of the
electron withdrawing effect of an electron withdrawing
group to the amide carbonyl, and preferably is selected
f rom among arylene , alkenyl , alkynyl and - ( CX'XS ) n-
moieties; Xl, Xz, X', X' and XS are independently selected
from among halo, hydrogen, alkyl, haloalkyl and cyano and
cyanoalkyl; and n is O, 1 or 2; provided that when n is
0, then at least one of X1, Xz and X3 is halo; and when Rp
is - (CX'XS)n- and n is 1 or 2, then at least one of X' and
XS is halo. Where any of X1, X2, X3, X' or XS is not halo,
it is preferably haloalkyl, most preferably perhaloalkyl.
Particularly preferred activators include those in which
n is 0 and at least two of X1, Xz and X3 are halo; or
those in which Rp is - (CX'XS) ~- , n is 1 or 2 , at least one
of X' and XS is halo, the other of X' and XS is halo or
perhaloalkyl, and X1, Xz and X3 are halo or perhaloalkyl.
Each of X1, X2 X3, X' and XS is preferably C1 or F, most
preferably Cl, though mixed halides may also be suitable,
CA 02550897 1997-12-11
as may perchloralkyl or perbromoalkyl and combinations
thereof, provided that the carbon directly attached to
the amide carbonyl is substituted with at least one halo
group.
5 Preferably, the peroxide activator is present
in a proportion of at least about 1 equivalent, more
preferably between about 1.5 and about 2 equivalents, per
equivalent of substrate initially present. Hydrogen
peroxide should be charged to the reaction in at least
10 modest excess, or added progressively as the epoxidation
reaction proceeds. Although the reaction consumes only
one to two equivalents of hydrogen peroxide per mole of
substrate, hydrogen peroxide is preferably charged in
substantial excess relative to substrate and activator
15 initially present. Without limiting the invention to a
particular theory, it is believed that the reaction
mechanism involves formation of an adduct of the
activator and the peroxide anion, that the formation of
this reaction is reversible with the equilibrium favoring
20 the reverse reaction, and that a substantial initial
excess of hydrogen peroxide is therefore necessary in
order to drive the reaction in the forward direction.
Temperature of the reaction is not narrowly critical, and
may be effectively carried out within the range of about
25 0° to about 100°C. The optimum temperature depends on
the selection of solvent. Generally, the preferred
temperature is between about 20°C and about 30°C, but in
certain solvents, e.g., toluene the reaction may be
advantageously conducted in the range of about 60° to
30 about 70°C. At about 25°C, reaction typically requires
less than about 10 hours, typically about 3 to about 6
hours. If needed, additional activator and hydrogen
peroxide may be added at the end of the reaction cycle to
achieve complete conversion of the substrate.
35 At the end of the reaction cycle, the aqueous
phase is removed, the organic reaction solution is
CA 02550897 1997-12-11
96
preferably washed for removal of water soluble
impurities, after which the product may be recovered by
removal of the solvent. Before removal of solvent, the
reaction solution should be washed with at least a mild
to moderately alkaline wash, e.g., sodium carbonate.
Preferably, the reaction mixture is washed successively
with: a mild reducing solution such as a weak fe.g. about
3% by weight) solution of sodium sulfite in water; an
alkaline solution, e.9., NaOH or KOH (preferably about
0.5N); an acid solution such as HC1 (preferably about
1N); and a final neutral wash comprising water or brine,
preferably saturated brine to minimize product losses.
Prior to removal of the reaction solvent, another solvent
such as an organic solvent, preferably ethanol may be
advantageously added, so that the product may be
recovered by crystallization after distillation for
removal of the more volatile reaction solvent.
It should be understood that the novel
epoxidation method utilizing trichloroacetamide or other
novel peroxide activator has application well beyond the
various schemes for the preparation of epoxymexrenone,
and in fact may be used for the formation of epoxides
across olefinic double bonds in a wide variety of
substrates subject to reaction in the liquid phase. The
reaction is particularly effective in unsaturated
compounds in which the olefins are tetrasubstituted and
trisubstituted, i . a . , RaRbC=CR'Ra and RaRbC=CR'H where Ra to
R° represent substituents other than hydrogen. The
reaction proceeds most rapidly and completely where the
substrate is a cyclic compound with a trisubstituted
double bond, or either a cyclic or acyclic compound with
a tetrasubstituted double bond. Exemplary substrates for
the epoxidation reaction include p9.11_canrenone, and the
following substrates:
CA 02550897 1997-12-11
97
o
O
IT /O
~~iii~~CO2CHa
p i p
O
O
O 0
\ \
O Me0
Because the reaction proceeds more rapidly and
completely with trisubstituted and tetrasubstituted
double bonds, it is especially effective for selective
epoxidation across such double bonds in compounds that
may include other double bonds where the olefinic carbons
are monosubstituted, or even disubstituted.
Other non-limiting examples illustrating the
generic epoxidation reaction include the following
epoxidation reactions:
CA 02550897 1997-12-11
98
0 0 0
AC
ACO Ac
H3C CH3 HOC CH3
H3C CH3
H3C CH9 . Ct
GH3 CH3
\ 0
H H
~CH3 ~ ~CH3
0
------w 0
H H
/ H H
~0
It should be further understood that the
reaction may be used to advantage in the epoxidation of
monosubstituted or even disubstituted double bonds, such
as the 11,12-olefin in various steroid substrates.
CA 02550897 1997-12-11
99
However, because it preferentially epoxidizes the more
highly substituted double bonds, e.g., the 9,11-olefin,
with high selectivity, the process pf this invention is
especially effective for achieving high yields and
productivity in the epoxidation steps of the various
reaction schemes described elsewhere herein.
The improved process has been shown to be a
particularly advantageous application to the preparation
of
0
0
/ mm~co cH
10. ° Z 3 IB
by epoxidation of:
~o
/0
mmnCp2CN~
and
the preparation of:
~o
o/
='o
0
IC
by epoxidation of:
CA 02550897 1997-12-11
100
O
Multiple advantages have been demonstrated for
the process of the invention in which trichloroacetamide
is used in place of trichloroacetonitrile as the oxygen
transfer reagent for the epoxidation reaction. The
trichloroacetamide reagent system has a low affinity for
electronically deficient olefins such as a,Q-unsaturated
ketones. This allows for selective epoxidation of a non-
conjugated olefin in substrates containing both types of
double bonds. Additionally, in complex substrates such
as steroids, disubstituted and trisubstituted olefins can
be differentiated by reaction. Thus, good selectivity is
observed in the epoxidation of the isomeric o-9,11 and 0-
11,12 compounds. In this case, the 9,11 epoxide is
formed with minimal reaction of the isomer containing the
D-11,12 double bond. Accordingly, reaction yield,
product profile and final purity are substantially
enhanced in comparison to reactions in which a
trihaloacetonitrile is used. It has further been
discovered that the substantial excess oxygen generation
observed with the use of trihaloacetonitrile is minimized
with trichloroacetamide, imparting improved safety to the
epoxidation process. Further in contrast to the
trichloroacetonitrile promoted reaction, the
trichloroacetamide reaction exhibits minimum exothermic
effects, thus facilitating control of the thermal profile
of the reaction. Agitation effects are observed to be
minimal and reactor performance more consistent, a
CA 02550897 1997-12-11
lol
further advantage over the trichloroacetonitrile process.
The reaction is more amenable to scaleup than the
trichloroacetonitrile promoted reaction. Product
isolation and purification is simple. There is no
observable Bayer-Villager oxidation of carbonyl function
(peroxide promoted conversion of ketone to ester) as
experienced when using m-chloroperoxybenzoic acid or
other peracids. The reagent is inexpensive, readily
available, and easily handled.
In addition, the following compounds have been
observed by chromatography in the crude product from the
step of the Scheme 1 synthesis in which the enester of
Formula II is converted to the compound of Formula I:
(1) the novel l1a,12a epoxide of the enester of
formula II, for example, 7-methyl hydrogen l1a,12a-epoxy-
17-hydroxy-3-oxo-17a-pregn-4-ene-7x,21-dicarboxylate, 'y-
lactone;
(2) the novel 4,5:9,11-diepoxide of the enester
of formula II, for example 7-methyl hydrogen
4a,5cx:9a,lla-diepoxy-17-hydroxy-3-oxo-17a-pregnane-7a,21-
dicarboxylate, y-lactone;
(3) the novel 12-ketone of the enester of
formula II, for example 7-methyl hydrogen 17-hydroxy-
3,12-dioxo-17a-pregna-4,9(11)-diene-7x,21-dicar~oxylate,
y-lactone;
(4) the novel 9,11-dihydroxy of the enester of
formula II, for example 7-methyl hydrogen 9a,11Q,17-
trihydroxy-3-oxo-17a-pregna-4-ene-7x,21-dicarboxylate, y-
lactone;
(5) the novel 12-hydroxy analog of the enester
of formula II, for example 7-methyl hydrogen 12a,17-
dihydroxy-3 -oxo- l7cr-pregna-4 , 9 ( 11 ) -diene-7cx, 21-
dicarboxylate, 'y-lactone; and
(6) the novel 7-acid of the compound of Formula
I, for example 9,lla-epoxy-17-hydroxy-3-oxo-17a-pregn-4-
ene-7x,21-dicarboxylic acid, y-lactone.
CA 02550897 1997-12-11
102
These compounds have utility as synthetic
intermediates and/or chromatographic markers in the
preparation of the compound of Formula I, particularly
epoxymexrenone.
The l1a,12a-epoxide of the enester of formula
II is hypothesized to form via an impurity produced
during the previous step in which a compound of formula
IV is converted to the enester of formula II. This
impurity was chromatographically isolated and is the pl.m
enester. It typically is produced with the p9,~1 enester
in a ratio of about 90:10 (~9m1 enester:pl~.~2 enester) ,
although this ratio can vary. Oxidation of the pl,lz
enester during the conversion of the enester of formula
II to the compound of Formula I yields the l1a,12a-
epoxide.
The 4,5:9,11-diepoxide of the enester of
Formula I was chromatographically isolated. It is
hypothesized to result from over-epoxidation of the
enester. It typically is observed in the crude product
at levels of about 5% by weight or less, although this
amount can vary .
The 12-ketone of the enester of Formula II was
chromatographically isolated. It is hypothesized to
result from allylic oxidation of the enester. It
typically is observed in the crude product at levels of
about 5% by weight or less, although this amount can
vary. The level of 12=ketone detected in the crude
product when trichloroacetonitrile was used as the
hydrogen peroxide activator was higher than the level
detected when trichloroacetamide was used as the
activator.
The 9,11-dihydroxy of the enester of Formula II
was chromatographically isolated. It typically is
observed in the crude product at levels of about 5% by
weight or less, although this amount can vary. It is
CA 02550897 1997-12-11
103
hypothesized to result from hydrolysis of the epoxide of
Formula I.
The 12-hydroxy of the enester of formula II
was chromatographically isolated. It typically is
observed in the crude product at levels of about 5% by .
weight or less, although this amount can vary. It is
hypothesized to result from hydrolysis of the 11,12
epoxide with subsequent elimination of the 11Q-hydroxy.
In addition, the compounds of Formula I
prepared in accordance with this disclosure can be
further modified to provide a metabolite, derivative,
prodrug or the like with improved properties (such as
improved solubility and absorption) ,which facilitate the
administration and/or efficacy of epoxymexrenone. The 6-
hydroxy of'the compound of Formula I (for example, 7-
methyl hydrogen 6J3,17-dihydroxy-9,lla-epoxy-3-oxo-17a-
pregn-4-ene-7a,21-dicarboxylate, 'y-lactone) is a novel
compound which has been identified as a possible
metabolite in the rat. The 6-hydroxy metabolite can be
prepared from the corresponding ethyl enol ether (for
example, 7-methyl hydrogen 9,lla-epoxy-3-ethoxy-17-
hydroxy-17a-pregn-4-ene-7a,21-dicarboxylate, ~y-lactone).
The ethyl enol ether of of the compound of Formula I can
be prepared in accordance with the procedure set forth in
R.M. Weier and L.M. Hofmann (J. Med Chem 1977, 1304).
The ethyl enol ether is then reacted with m-
chloroperbenzoic acid to yield the corresponding 6-
hydroxy of the compound of Formula I.
It is further hypothesized that the
monocarboxylic salts of epoxymexrenone, particularly the
potassium and sodium salts, are suitable alternatives to
facilitate administration of a compound of Formula I to
an individual for whom administration of an aldosterone
antagonist is indicated. Under mild basic conditions it
is possible to selectively open the spirolactone of the
CA 02550897 1997-12-11
104
compounds of Formula I without hydrolyzing the C7 ester
substituent to give the corresponding 178-hydroxy-17a-(3-
propionic acid) analog. These open chain analogs are
more polar than their lactone counterparts and have
shorter retention times when analyzed by reverse phase
HPLC. Acidic conditions generally cause the. regeneration
of the lactone ring.
Under more forcing conditions, the spirolactone
is opened and the C7 ester is hydrolyzed to give the
corresponding by-products, 178-hydroxy-17a-(3-propionic
acid)-7-acid analogs of the compounds of Formula I.
These dicarboxylic acids have shorter retention times
than the monocarboxylic acids when analyzed by reverse
phase HPLC. Acidic conditions (e.g., treatment with a
dilute acid such as 0.1-4 M hydrochloric acid) generally
cause the regeneration of the lactone ring of the
dicarboxylic acid.
The novel epoxidation method of the invention
is highly useful as the concluding step of the synthesis
of Scheme 1. In a particularly preferred embodiment; the
overall process of Scheme 1 proceeds as follows:
CA 02550897 1997-12-11
105
0 0
.ICI. DIAF. E1~H.
loveen~ oyuahpdeln,
~IfyAtoxyl~tbn t6 'C, 1~1f h
C~nr ~nen~ tta-Hydroxywnnmn~
O
O
1. U~CI, Et~H. 1. N~OCH~. CH~OH.
CHlCIx, nftux
-10~C m 10~C
Hydrosye~er O
1A vsy4tv
HCOOH. HCOOK, Ae=O,
I 70' C, 1f h
O
CIxC-C(O)-NHZ. HpOi. CI
10' C. 24 h
EM~let
Epo:yn~xnnon~
Scheme 2
The second of the novel reaction schemes
tScheme 2) of this invention starts with canrenone or
other substrate corresponding to Formula XIII
R3
r, 8
R9
XIII
HC4 CH~OH, H=O.
80 ' C. 6h
CA 02550897 1997-12-11
106
where -A-A-, -H-H-, R', Re and R9 are as defined in
Formula XIII. In the first step of this process, the
substrate of Formula XIII is converted to a product of
Formula XII
R3
R9
C
I
NHZ
XII
using a cyanidation reaction scheme substantially the
same as that described above for conversion of the
substrate of Formula VIII to the intermediate of Formula
VII. Preferably, the substrate of Formula XIII
corresponds to Formula XIIIA
p3 Y2
y~
~.v\\~ CH2~'2 C-X
CH3 B
A
,q i B
/~
XIIIA
and the enamine product corresponds to Formula XIIA
CA 02550897 1997-12-11
1~7
Y2
R'~ . I
CH -C-X
~~C 2) z
' X11A
in each of which -A-A-; -B-B-, R', 1, Yz, and X are as
defined in Formula XIIIA. Preferably, R3 is hydrogen
In the second step of Scheme 2, the enamine of
Formula XII is hydrolyzed to an intermediate diketone
product of Formula XI
R3 08
R9
XI
where -A-A- , -B-B- , R3 , RB and R9 are as def fined in
Formula XIII, using a reaction scheme substantially the
same as that described above for conversion of the
substrate of Formula VIII to the intermediate of Formula
VII. Preferably, the substrate of Formula XII
corresponds to Formula XIIA
CA 02550897 1997-12-11
108
Y2
R
2~ z C-X
t
NH2
XIIA
and the diketone product corresponds to Formula XIA
R3 yZ
Y~
3~ \\\~~Cfj2~2 C-X
~H3 ~g
A
q~ 8
I .CN
.:
r~
XIA
in each of which -A-A-, -B-B-, R3, yl, y2, and X are as
defined in Formula XIIIA. Preferably, R' is hydrogen.
Further in accordance with reaction scheme 2,
the diketone of Formula XI is reacted with an alkali
metal alkoxide to form mexrenone or other product
corresponding to Formula X,
R3
ne
Rg
3
X
in each of which -A-A- , -B-B- , R3 ; R8 and R9 are as
defined in Formula XIII, and R1 is as defined in Formula
V. The process is carried out using substantially the
CA 02550897 1997-12-11
109
same reaction scheme that is described above for the
conversion of the compounds of Formula VI to those of
Formula V. Preferably, the substrate of Formula XI
corresponds to Formula XIA
R3 Y2
'\( CHZ~ z C~X
B
,:
fl
~ XIA
and the intermediate product corresponds to Formula XA
as Y 2
Y~ ,
~~ \''~(CHZ~2 C=X
CH3 B
A
8
0 '~~,R ~
XA
in each of which -A-A-, -B-B-, R3, Y1, Y~, and X are as
defined in Formula XIIIA, and R1 is as defined in Formula
V. Preferably, R' is hydrogen.
Mexrenone and other compounds of Formula X are
next 9a-hydroxylated by a novel bioconversion process to
yield products of Formula IX
R3 8
R 9
R
iA ,.OOH iB
A B
/ .,~iR ~
IX
where -A-A- , -B-B- , R' , Re and R9 are as def fined in
Formula XIII, and R1 is as defined in Formula V. Among
CA 02550897 1997-12-11
110
the organisms that can be used in this hydroxylation step
are Nocardia conicruria ATCC 31548, Nocardia aurentia
ATCC 12674, Corvnespora cassiicola ATCC 16718,
Stre~tomvces hvdroscopicus ATCC 27438, Mortierella
isabellina ATCC 42613, Beauvria bassiana ATCC 7519,
Penicillum~urnuroQenum ATCC 46581, Hvnomyces
chrysospermus IMI 109891, Thamnostvlum piriforme ATCC
8992, Cunninahamella blakesleeana ATCC 8688a,
Cunninahamella echinulata ATCC 3655, Cunnindhamella
eleQans ATCC 9245, Trichothecium roseum ATCC 12543,
E~icoccum humicola ATCC 12722, Saccharonolvspora eythrae
ATCC 11635, Beauvria bassiana ATCC 13144, Arthrobacter
simplex, Bacterium cyclooxydans ATCC 12673,
Cylindrocarnon radicicola ATCC 11011, Nocardia aurentia
ATCC 12674, Norcardia restrictus ATCC 14887, Pseudomonas
testosterone ATCC 11996, Rhodococcus equi ATCC 21329,
Mycobacterium fortuitum NRRL 88119, and Rhodococcus
rhodochrous ATCC 19150. The reaction is carried out
substantially in the manner described above in connection
with Figs. 1 and 2. The process of Fig. 1 is
particularly preferred.
Growth media useful in the bioconversions
preferably contain between about 0.05% and about 5% by
weight available nitrogen; between about 0.5% and about
5% by weight glucose; between about 0.25% and about 2.5%
by weight of a yeast derivative; and between about 0.05%
and about 0.5% by weight available phosphorus:
Particularly preferred growth media include the
following:
soybean meal: between about 0.5% and about 3% by weight
glucose; between about 0.1% and about 1% by weight
soybean meal; between about 0.05% and about 0.5% by
weight alkali metal halide; between about 0.05% and about
0.5% by weight of a yeast derivative such as autolyzed
CA 02550897 1997-12-11
111
yeast or yeast extract; between about 0.05% and about
0.5% by weight of a phosphate salt such as ICzHPO,; pH = 7;
peptone-yeast extract-glucose: between about 0.2% and
about 2% by weight peptone; between about 0.05% and about
0.5% by weight yeast extract; and between about 2% and
about 5% by weight glucose;
Mueller-Hinton: between about 10% and about 40% by
weight beef infusion; between about 0.35% and about 8.75%
by weight casamino acids; between about 0.15% and about
0.7% by weight starch.
Fungi can be grown in soybean meal or peptone
nutrients, while actinomycetes and eubacteria can be
grown in soybean meal (plus 0.5% to 1% by weight
carboxylic acid salt such as sodium formate for
biotransformations) or in Mueller-Hinton broth.
The production of ll~i-hydroxymexrenone from
mexrenone by fermentation is discussed in Example 19B.
Similar bioconversion processes can be used to prepare
other starting materials and intermediates. Example 19A
discloses the bioconversion of androstendione to 11~8-
hydroxyandrostendione. Example 19C discloses the
bioconversion of mexrenone to lla-hydroxymexrenone, pl.z-
mexrenone, 6(3-hydroxymexrenone, 128-hydroxymexrenone, and
9a-hydroxymexrenone. Example 19D discloses the
bioconversion of canrenone to ~9m1-canrenone.
The products of Formula IX are novel compounds,
which may be separated by filtration, washed with a
suitable organic solvent, e.g., ethyl acetate, and
recrystallized from the same or a similar solvent. They
have substantial value as intermediates for the
preparation of compounds of Formula I, and especially of
Formula IA. Preferably, the compounds of Formula IX
correspond to Formula IXA in which -A-A- and -B-B- are
CA 02550897 1997-12-11
112
-CH2-CHZ-. R3 is hydrogen, lower alkyl or lower alkoxy.
and Re and R9 together constitute the 20-spiroxane ring:
0
~~
0
,n XXXI I I
In the next step of the Scheme 2 synthesis, the
product of Formula IX is reacted with a dehydration
reagent (suitable dehydration reagents such as PhSOCl or
C1S03H are known to persons skilled in the art) to produce
a compound of Formula II
R3 RB
R9
B
B
0 % / yii R 1
II
wherein -A-A-, -H-H-, R3, R8 and R9 are as defined in
Formula XIII, and R1 is as defined in Formula V.
Preferably, the substrate of Formula IX corresponds to
Formula IXA
R3 Y 2
1
H3~ Y \\'~~ CH2~ Z C-X
CH3 \~~OH B
A
8
,~iR 1
IXA
and the intermediate product corresponds to Formula IIA
CA 02550897 1997-12-11
113
H3C Y2
R3 Yt
-C-X
~~~~C CH2) 2
CH3~
,q~A B
O / i,~~ R ~
IIA
in each of which -A-A-, -B-H-, R3, Y1, Yz, and X are as
defined in Formula XIIIA; and Rl is as defined in Formula
V. Preferably, R' is hydrogen.
In the final step of this synthesis scheme, the
product of Formula II is converted to that of Formula I
by epoxidation in accordance with the method described in
U.S. patent 4,559,332; or preferably by the novel
epoxidation method of the invention as described
hereinabove.
In a particularly preferred embodiment, the
overall process of Scheme 2 proceeds as follows:
CA 02550897 1997-12-11
114
0 0 0
LICI. DMF, EI~N, ,
Acetone c~anohy0rm, CI, CH~OH, Hz0
85' C. 8-15 h 0' C, Sh
Canranon!
1. Na0CH3. CH30H, reflu:
0 2. RlttyStaaZ! (f0m CHZCIZ,
TOIUln!
'''0 H
0
~~~~COOCH3
9~a-Hyoroxymexrenone
Novel
Bacolverston
PhSOCI, or C1503H
0 '
Enesler Mlarenone
C13C-C(0)NH2. HZOz. CHZCIZ,
10' C, 2~ h
0 CH3
11~B-HyCro>;ymexreaone
Epoaymexrenone
Scheme 3
The synthesis in this case begins with a
substrate corresponding to Formula XX
Ra
H~ C
CH9 I 'B
/A i
A
\ \
0
1111
where -A-A- and R3 are as defined in Formula XIII, -H-H-
is as defined in Formula XIII except that neither R6 nor
CA 02550897 1997-12-11
115
R' is part of a ring fused to the D ring, at the 16,17
positions, and RZ6 is lower alkyl, preferably methyl.
Preferably, R' is hydrogen. Reaction of the substrate of
Formula XX with a sulfonium ylide produces the epoxide
intermediate corresponding to Formula XIX .
0
H 3 C ''~
CH31 B
- AAA 6
8260 \ \
XIX
wherein -A-A-, -H-H-, R' and R~6 are as defined in Formula
XX. Preferably, R' is hydrogen.
In the next step of synthesis scheme 3; the
intermediate of Formula XIX is converted to a further
intermediate of Formula XVIII
0
COp Et
HaC O
IIn
CH9 I ~B
A A i
o XVIII
wherein -A-A-, -B-H- and R' are as defined in Formula XX.
Preferably, R3 is hydrogen. In this step, Formula XIX
substrate is converted to Formula XVIII intermediate by
reaction with NaCH(COOEt)z in the presence of a base in a
solvent.
Exposure of the compound of Formula XVIII to
heat, water and an alkali halide produces a
decarboxylated intermediate compound corresponding to
Formula XVII
CA 02550897 1997-12-11
116
0
Ra
HOC ~
ntt
CH9 ~ \B
AiA 9
XVII
wherein -A-A-, -B-B- and R' are as defined in Formula XX.
Preferably, R' is hydrogen. The process for conversion of
the compound of Formula XX to the compound of Formula
XVII corresponds essentially to that described in U.S.
patents 3,897,417, 3,413,288 and 3,300,489. While the
substrates differ, the reagents, mechanisms and
conditions for introduction of the 17-spirolactone moiety
are essentially the same.
Reaction of the intermediate of Formula XVII
with a dehydrogenation reagent yields the further
intermediate of Formula XVI.
0
R3 O
It
B
XVI
where -A-A-, -H-B- and R3 are as defined in Formula XX.
Preferably, R3 is hydrogen.
Typically useful dehydrogenation reagents
include dichlorodicyanobenzoquinone (DDQ) and chloranil
(2,3,5,6-tetrachloro-p-benzoquinone~). Alternatively, the
dehydrogenation could be achieved by a sequential
halogenation at the 6-position carbon followed by
dehydrohalogenation reaction.
CA 02550897 1997-12-11
117
The intermediate of Formula XVI is next
converted to the enamine of Formula XVB
0
R~
HaCO
CH9~ ~ ~B
AiA B
CN
C
NHp
wherein -A-A-, -B-B- and R3 are as defined in Formula XX.
Preferably; R3 is hydrogen.. Conversion is by cyanidation
essentially in the manner described above for the
conversion of the Ila-hydroxy compound of Formula VIII to
the enamine of Formula VII. Typically, the cyanide ion
source may be an alkali metal cyanide. The base is
preferably pyrrolidine and/or tetramethylguanidine. A
methanol solvent may be used.
The products of Formula XVB are novel
compounds, which may be isolated by chromatography.
These and other novel compounds of Formula XV have
substantial value as intermediates for the preparation of
compounds of Formula I, and especially of Formula IA.
Compounds of Formula XV correspond to the structure
Rs
c
NH2 XV
03
CA 02550897 1997-12-11
118
where -A-A- , -B-B- , R' , R8 and R9 are as defined in
Formula XIII. In the most preferred compounds of Formula
XV and Formula XVB, -A-A- and -B-B- are -CH2-CHz-, and R'
is hydrogen.
In accordance with the hydrolysis described
above for producing the diketone compounds of Formula VI,
the enamines of Formula XVB may be converted to the
diketones of Formula XIVH
0
R$
H'C~
CHe l 'B
AiA B
I _CN
XIVB
wherein -A-A-, -B-H- and R3 are as defined in Formula XX.
Preferably, R' is hydrogen. Particularly preferred for
the synthesis of epoxymexrenone are those compounds of
Formula XIV which also fall within the scope of Formula
XIVB as defined below.
The products of Formula XIVB are novel
compounds, which may be isolated by precipitation. These
and other novel compounds of Formula XIV have substantial
value as intermediates for the preparation of compounds
of Formula I, and especially of Formula IA. Compounds of
Formula XIV correspond to the structure
CA 02550897 1997-12-11
119
o~
R9
3
fl
XIV
where -A-A- , -B-B- , R3 , R8 and R9 are as ~def fined in
Formula XIII. In the most preferred compounds of Formula
XIV and XIVB, -A-A- and -B-B- are -CHz-CHZ-, and R3 is
hydrogen.
The compounds of Formula XIVB are further
converted to compounds of Formula XXXI using essentially
the process described above for converting the diketone
of Formula VI to the hydroxyester of Formula V. In this
instance, it is necessary to isolate the intermediate
XXXI
0
p3
H3C
IIII
CH3~ \B
A
A~
~~~i,R ~
XXXI
before further conversion to a product of Formula XXXII
0
H3C
R3 0
IIIiI
.8
i
B
iiii R 1
XXXII
CA 02550897 1997-12-11
120
wherein -A-A-, -B-B- and R' are as defined in Formula XX,
and R1 is as defined in Formula V. Preferably, R' is
hydrogen. Preferred compounds of Formula XXXI are those
which fall within Formula IIA. The compounds of Formula
XXXI are converted to compounds of Formula XXXII using
the method described hereinabove or in U.S. patent
4,559,332.
Preferably, the compound of Formula XIV is
4'S(4'cx),7'a-1',2',3',4,4',5,5',6',7',8',10',12',13',
14',15',16'-hexadecahydro-10/3-,13'/3-dimethyl-3',5,20'-
trioxospiro [furan-2 (3H) , 17' (3- [4, 7] methano [17H] -
cyclopenta[a]phenanthrene]5'-carbonitrile; and the
compound of Formula XV is 5'R(5'a),7'~i-20'-amino-
1',2',3',4,5, 6',7',8', 10',12',13',14',15',16'-
tetradecahydro-l0'a,13'a-dimethyl-3',5-dioxospiro[furan-
2 ( 3H) , 17' a ( 5' H) - [7 , 4 ] metheno [4H] -
cyclopenta[a]phenanthrene]-5'-carbonitrile. In a
particularly preferred embodiment, the overall process of
Scheme 3 proceeds as follows:
CA 02550897 1997-12-11
121
0 0' COtEt
~v
Sullonlum ~ NaCH(COOEt)q
\ \ \
Me0 Ylbe Me0
Heat
Na C 1
DtA50
p 0 0
KCN, Pyff0110me, El3N
Trlmelhylpuanlome~ 0 ar Chloreno
MeOH
HCI.
CH~OH,
HZO
80
'
C,
Sh
O
O
0
1. NaOCH~, CH30H,
rellux p
HI~
~
2. Recrystaa:eo C13C(O)-NNa, HZOZ.
Irom CHZCI~ CI
a
Toluene I TOC, 21 h
CN
O 0 / ~~~rCOOCH3
Epoxymexrenone
0
Scheme 4
The first three steps of Scheme 4 are the same
as those of Scheme 3, i.e.. preparation of an
intermediate of Formula XVII starting with a compound
corresponding to Formula XX.
Thereafter, the intermediate of Formula XVII is
epoxidized, for example, using the process of U.S: patent
4,559,332 to produce the compound of Formula XXIV
CA 02550897 1997-12-11
122
0
H3C
R3 0
....1
B
XXIV
wherein -A-A-, -B-B- and R3 are as defined in Formula XX.
However, in a particularly preferred embodiment of the
invention, the substrate of Formula XVII is epoxidized
across the 9,11-double bond using an oxidation reagent
comprising an amide type peroxide activator, most
preferably trichloroacetamide, according to the process
as described above in Scheme 1 for the conversion of the
enester of Formula II to the product of Formula I. The
conditions and proportions of reagents for this reaction
are substantially as described for the conversion of the
Formula II enester to epoxymexrenone. Particularly
preferred compounds of Formula XXIV are those in which
-A-A- and -H-B- are as defined in Formula XI LT and R' is
hydrogen.
It has been found that the epoxidation of the
substrate of Formula XVII can also be effected in very
good yield using a peracid such as, for example, m-
chloroperoxybenzoic acid. However, the
trichloroacetamide reagent provides superior results in
minimizing the formation of Bayer-Villager oxidation by-
product. The latter by-product can be removed; but this
requires trituration from a solvent such as ethyl
acetate, followed by crystallization from another solvent
such as methylene chloride. The epoxy compound of
Formula XXIV is dehydrogenated to prflduce a double bond
between the 6- and ?-carbons by reaction with a
dehydrogenation (oxidizing) agent such as DDQ or
chloranil, or using the bromination/dehydrobromination
CA 02550897 1997-12-11
123
(or other halogenation/dehydrohalogenation) sequence, to
produce another novel intermediate of Formula XXIII
H3C
R3 RB
i ~ v R9
CN3~ ~~~~ 8
A ~~
A/ 8
XXIII
wherein -A-A-, -H-B-, R', RB and R9 are as defined in
Formula XX.
Particularly preferred compounds of Formula XXIII are
those in which -A-A- and -B-B- are as defined in Formula
XIII and R3 is hydrogen.
While direct oxidation is effective for the
formation of the product of Formula XXIII, the yields are
generally low. Preferably, therefore, the oxidation is
carried out in two steps, first halogenating the
substrate of Formula XXIV at the C-6 position, then
dehydrohalogenating to the 6,7-olefin. Halogenation is
preferably effected with an N-halo organic reagent such
as, for example, N-bromosuccinamide. Bromination is
carried out in a suitable solvent such as, for example,
acetonitrile, in the presence of halogenation promoter
such as benzoyl peroxide. The reaction proceeds
effectively at a temperature in the range of about 50° to
about 100°C, conveniently at atmospheric reflux
temperature in a solvent such as carbon tetrachloride,
acetonitrile or mixture thereof. However, reaction from
4 to 10 hours is typically required for completion of the
reaction. The reaction solvent is stripped off, and the
residue taken up in a water-immiscible solvent, e.g.,
ethyl acetate. The resulting solution is washed
sequentially with a mild alkaline solution (such as an
alkali metal bicarbonate) and water, or preferably
saturated brine to minimize product losses, after which
CA 02550897 1997-12-11
124
the solvent is stripped and a the residue taken up in
another solvent (such as dimethylformamide) that is
suitable for the dehydrohalogenation reaction.
A suitable dehydrohalogenation reagent, e.g.,
1,4-diazabicyclo[2,2,2]octane (DABCO) is added to the
solution, along with an alkali metal halide such as Liar,
the solution heated to a suitable reaction temperature,
e.g., 60° to 80°C, and reaction continued for several
hours, typically 4 to 15 hours, to complete the
dehydrobromination. Additional dehydrobromination
reagent may be added as necessary during the reaction
cycle, to drive the reaction to completion: The product
of Formula XXILI may then be recovered, e.g., by adding
water to precipitate the product which is then separated
by filtration and preferably washed with additional
amounts of water. The product is preferably
recrystallized, for example from dimethylformamide.
The products of Formula XXIII, such as 9,11-
epoxycanrenone, are novel compounds, which may be
isolated by extraction/crystallization. They have
substantial value as intermediates for the preparation of
compounds of Formula I, and .especially of Formula IA.
For example, they may be used as substrates for the
preparation of compounds of Formula XXII.
Using substantially the process described above
for the preparation of compounds of Formula VII, the
compounds of Formula XXIII are reacted with cyanide ion
to produce novel epoxyenamine compounds corresponding to
Formula XXII
CA 02550897 1997-12-11
125
H3C
R
Rg
i,~~
I 3 \\\ p / B
8
C
N H z XXI I
wherein -A-A-, -B-B-, R3, Re and R9 are as defined in
Formula XX. Particularly preferred compounds of Formula
XXII are those in which -A-A- and -B-B- are as def ined-in
Formula XIII and R3 is hydrogen.
The products of Formula XXII are novel
compounds, which may be isolated by precipitation and
filtration. They have substantial value as intermediates
for the preparation of compounds of Formula I, and
especially of Formula IA. In the most preferred
compounds of Formula XXII, -A-A- and -B-B- are -CH2-CH2-,
and R3 is hydrogen.
Using substantially the process described above
for preparation of compounds of Formula VI, the
epoxyenamine compounds of Formula XXII are converted to
novel epoxydiketone compounds of Formula XXI
H C
R3 8
I ~ R R9
CH3 'gyp B
q v~ /
B
I _CN
v v.-
fl
p xxI
CA 02550897 1997-12-11
126
wherein -A-A-, -B-B-, R', R8 and R9 are as defined in
Formula XIII. In the most preferred compounds of Fflrmula
XXI , -A-A- and -B-H- are -CHz-CHz- and R' is hydrogen.
The products of Formula XXI are novel
compounds, which may be isolated by precipitation and
filtration. They have substantial value as intermediates
for the preparation of compounds of Formula I, and
especially of Formula IA. Particularly preferred
compounds of Formula XXI are those in which -A-A- and -B-
B- are as defined in Formula XIII. In the most, preferred
compounds of Formula XXI, -A-A- and -B-B- are -CHZ-CHz-
and R3 is hydrogen.
Using substantially the process described above
for preparation of the hydro~cyester compounds of Formula
V from the diketone compounds of Formula VI, the
epoxydiketone compounds of Formula XXI are converted to
compounds of Formula XXXII
H3C
R3
A
A
0
rill
CH3~~~~
B
~'~ ~R XXXII
wherein -A-A-, -B-B- and R3 are as defined in Formula XX,
and R1 is as defined in Formula V.
As in the conversion of the diketone of formula
V to the hydroxyester of formula VI, a 5-(3-cyano-7-ester
intermediate is also formed in the conversion of the
epoxydiketone of formula XXI to compounds of formula
XXXII. The 5-,~-cyano-7-ester intermediates in both
series can be isolated by treatment of the corresponding
diketone with an alcohol such as methanol in the presence
CA 02550897 1997-12-11
127
of a base such as triethylamine. Preferably, the
intermediates are prepared by refluxing a mixture of the
diketone in an alcohol such as methanol containing about
0.1 to about 2 equivalents of triethylamine per mole of
diketone for about 4 to about 16 hours. The products are
isolated in pure form by cooling the mixture to about 25
degrees followed by filtration. The isolated
intermediates can be converted to the compounds of
Formula XXXII on treatment with a base such an alkali
metal alkoxide in a solvent, preferably an alcohol such
as methanol. Use of an alkoxide in an alcohol
establishes an equilibrium mixture similar to that formed
when the corresponding diketone of Formula XXI is treated
under the same conditions.
In addition, the 7/3-ester of the compound of
Formula XXXII (for example 7-methyl hydrogen 9;lla-epoxy-
17-hydroxy-3-oxo-17a-pregn-4-ene-7~i,21-dicarboxylate, 'y-
lactone) has been observed by chromatography in the crude
product of the final step of the process of Scheme 4.
Alkoxide and/or cyanide in the solution reacts with and
converts the 7a-ester into an epimeric mixture of the 7a-
ester and its 7~i-ester epimer. The pure 7(3-ester can be
isolated from the epimeric mixture by selective
crystallization.
Preferably, the compound of Formula XXI is
4'S(4'a),7'a-9',lla-epoxyhexadecahydro-lOf3-,13'Q-
dimethyl-3' 5, 20' -trioxospiro [furan-2 (3H) , 17' ~i-
[4, 7] methano [17H] -cyclopenta [a] phenanthrene-5' -
carbonitrile; the compound of Formula XXII is
5'R(5'a),7'~i-20'-amino-9,ll~i-epoxyhexadecahydro-10',13'-
dimethy1-3' , 5-dioxospiro [furan-2 (3H) , 17' a (5'H) -
[7, 4] methene [4H] cyclopenta [a] phenanthrene-5' -
carbonitrile; and the compound of Formula XXIII is 9,lla-
epoxy-17a-hydroxy-3-oxopregna-4,6-diene-21-carboxylic
acid, y-lactone.
CA 02550897 1997-12-11
128
In a particularly preferred embodiment, the
overall process of Scheme 4 proceeds as follows:
0
0 0
.... o
I I ''~o
,,, .
4 Sieps c~3C~C(0).NMZ.~io~.cNZey
\ \ ~ / ~o~ ma ~ -
Me 0 0 0
ODO or Cnloranil
O
HCI . CH~OH, H veeteev erenenye
80~C, 5~ TNG DNF
NH2
HeOCH~.CH~OH,
~mlW x
~DOxylnexrlnon6
Scheme 5
The process of scheme 5 begins with a substrate
corresponding to Formula XXIX
H,C
CH3 B
A
~'B
XXIX
CA 02550897 1997-12-11
129
wherein -A-A-, -B-B- and R' are as defined in Formula XX.
The following microorganisms are capable of carrying out
the 9a-hydroxylation of a compound of Formula XXXV (such
as androstendione)
R9
n
B
XXXV
wherein -A-A-, -B-B- and R3 are as defined in Formula
XIII, to a compound of Formula XXIX under conditions
similar to those described in Example 19H:
AsperiQillus niQer ATCC 16888 and 26693,
Corvnespora cassiicola ATCC 16718, Curvularia clavata
ATCC 22921, Mycobacterium fortuitum NRRL B8119, Nocardia
canicruria ATCC 31548, PYCIlOSDOrlum spp. ATCC 12231,
Stysanus microsporus ATCC 2833, Syncephalastrum racemosum
ATCC 18192, and Thamnostylum piriforme ATCC 8992.
The substrate corresponding to Formula XXIX is
converted to a product of Formula XXVIII
R3
0
B
A ~
OH
\ \
Meo XXVIII
by reaction with trimethylorthoformate, wherein -A-A-,
-B-B- and R' are as defined in Formula XX. Following the
formation of the compounds of Formula XXVIII, those
compounds are converted to the compounds of Formula XXVII
using the method described above for conversion of the
CA 02550897 1997-12-11
130
substrate of Formula XX to Formula XVII. Compounds of
Formula XXVII have the structure:
H3C
R3
0
niir
t
CH3 B
Ai A B
0R"T
XXVII
wherein -A-A-, -H-B- and R' are as defined in Formula XX,
and R" is any of the common hydroxy protecting groins.
Alternatively, the C9 a-hydroxy group can be protected at
an earlier step in this synthesis scheme if protection at
that step is desired, i.e., the C9 hydroxy of the
compound of Formula XXVIII or the C9 hydroxy of the
compound of Formula XXIX can be protected with any of the
common hydroxy protecting groups.
Using the method described above for 'the
preparation of compounds of Formula XVI, compounds of
Formula XXVII are oxidized to yield novel compounds
IS corresponding to Formula XXVI
0
H3C
R3 0
W n
CH3 ~B
A
A/ _ ~B
OR"
/ /
XXVI
wherein -A-A-, -H-H- and R3 are as defined in Formula XX.
Particularly preferred compounds of Formulae XXIX,
XXVIII, XXVII and XXVI are those in which -A-A- and -B-B-
are as defined in Formula XIII, and R' is hydrogen.
The products of Formula XXVI are novel
compounds, which may be isolated by precipitation/
filtration. They have substantial value as intermediates
CA 02550897 1997-12-11
131
for the preparation of compounds of Formula T, and
especially of Formula IA. Particularly preferred
compounds of Formula XXVI are those in which -A-A- and -
B-B- are as defined in Formula XIII, and R' is hydrogen.
In the most preferred compounds of Formula XXVI, and -A-
A- and -B-B- are -CHZ-CH2-, and R' is hydrogen.
Using the method defined above for cyanidation
of compounds of Formula VIII, the novel intermediates of
Formula XXVI are converted to the novel 9-hydroxyenamine
intermediates of Formula XXV
0
H3C
R3 0
W 11
,- \
CH ORx 8
p 3 ~~~~
CN
0/ V~
.~
C'
NHZ
XXV
wherein -A-A-, -B-B- and R' are as defined in Formula XX.
The products of Formula XXV are novel
compounds, which may be isolated by precipitation/
filtration. They have substantial value as intermediates
for the preparation of compounds of Formula I, and
especially of Formula IA. Particularly preferred
compounds of Formula XXV are those in which -A-A- and -B-
B- are as defined in Formula XIII, and R' is hydrogen. In
the most preferred compounds of Formula XXVI, and -A-A-
and -B-B- are -CHZ-CHZ-, and R' is hydrogen.
Using essentially the conditions described
above for the preparation of the diketone compounds of
Formula VI, the 9-hydroxyenamine intermediates of Formula
XXV are converted to the diketone compounds of Formula
XIVB. Note that in this instance the reaction is
effective for simultaneous hydrolysis of the enamine
CA 02550897 1997-12-11
132
structure and dehydration at the 9,11 positions to
introduce the 9,11 double bond. The compound of Formula
XIV is then converted to the compound of Formula XXXI,
and thence to the compound of Formula XIII, using the
same steps that are described above in scheme 3.
Preferably, the compound of Formula XIV is
4'S(4'a),7'a-1',2',3',4,4',5,5',6',7',8',10',
12',13',14',15',16'-hexadecahydro-10~i-,I3'~'-dimethyl-
3' , 5, 20' -trioxospiro [furan-2 (3H) ,17' ~- [4, 7] methano [17H] -
cyclopenta[a]phenanthrene]5'-carbonitrile; the compound
of Formula XXV is 5'R(5'a),7'/3-20'-aminohexadecahydro-
9'/3-hydroxy-10'a,13'a-dimethyl-3',5-dioxospiro[furan-
2 ( 3H) ,17' a ( 5' H) - [ 7 , 4 ] metheno [4H] cyclopenta [a]
phenanthrene]-5'-carbonitrile; the compound of Formula
XXVI is 9a,17cr-dihydroxy-3-oxopregna-4,6-diene-21-
carboxylic acid, y-lactone; and the compound of Formula
XXVII is 9a,17a-dihydroxy-3-oxopregn-4-ene-21-carboxylic
acid, y-lactone.
In a particularly preferred embodiment, the
overall process of Scheme 5 proceeds as follows:
CA 02550897 1997-12-11
133
0
0 0 0
~ ....
_ 4 St:apa
Op~ (Me0~3CH OR ----~ OR"
~MeO \ \ 0
0
DDO or t:hloranil
0 0 0
O
hiii
HCI, CH30H, HzO. acetone cyanonyann
eo~ c. 5 n
CN, MG. DMF
0
NH2
NaOCH3, CH30H,
rellu=
O O
0
mn C13CCN, HzOz. CHzCl2.
10~ C, 2a n
0 / ~~~~COOCH3
EDOxymexrenone
Scheme 6
Scheme 6 provides an advantageous method for
the preparation of epoxymexrenone and other compounds
corresponding to Formula I, starting with lla or ll~i-
hydroxylation of androstendione or other compound of
Formula XXXV
Rs
n
B
CA 02550897 1997-12-11
134
wherein -A-A-, -B-B- and R' are as defined in Formula
XIII, producing an intermediate corresponding to the
Formula XXXVI or its corresponding ll~i-hydroxy isomer
B
XXXVI
where -A-A-, -B-B- and R3 are as define3 in Formula XIII.
Except for the selection of substrate, the process for
conducting the lla-hydroxylation is essentially as
described hereinabove for Scheme 1: The following
microorganisms are capable of carrying out the 11a-
hydroxylation of androstendione or other compound of
Formula XXXV-..
Absidia crlauca ATCC 22752, Asperaillus flavipes
ATCC 1030, As"percrillus foetidus ATCC 10254, AsDeraillus
fumiaatus ATCC 26934, Asperaillus ochraceus NRRL 405
(ATCC 18500) , Aspercrillus ni er ATCC 11394, AsnercTillus
nidulans ATCC 11267, Beauveria bassiana ATCC 7159,
Fusarium oxvsnorum ATCC 7601, Fusarium oxysporum ce~ae
ATCC 11171, Fusarium lini ATCC IFO 7156, Gibberella
fu~ikori ATCC 14842, Hypomvces chvrsos_permus IMI 109891,
Mvcobaterium fortuitum NRRL 88119, Penicillum patulum
ATCC 24550, Pycnosaorium spp. ATCC 12231, Rhizoaus
arrhizus ATCC 11145, Saccharooolvsoora ervthraea ATCC
11635, Thamnostylum piriforme ATCC 8992, Rhizor~us or~rzae
ATCC 11145, Rhizopus stolonifer ATCC 622?b, and
Trichothecium roseum ATCC 12519 and ATCC 8685.
The following microorganisms are capable of
carrying out the ll~i-hydroxylation of androstendione or
other compound of Formula XXXV:
AsperQillus fumiQatus ATCC 26934, Asnergvillus
niQer ATCC 16888 and ATCC 26693, Epicoccum orvzae ATCC
CA 02550897 1997-12-11
135
7156, Curvularia lunata ATCC 12017, Cunninqhamella
blakesleeana ATCC 8688a, and Pithomyces atro-olivaceous
IFO 6651.
llcx-Hydroxyandrost-4-ene-3,17-dione, or other
compound of Formula XXXVI, is next converted to lla-
hydroxy-3,4-enol ether of Formula (101):
R$
O
H 0,~~~
B
Bi
J~\
Rt ~ ~~, _ _
101
where -A-A-, -B-e- and R3 are as defined in Formula XIII
and R11 is methyl or other lower alkyl (C1 to C,) , by
reaction with an etherifying reagent such as trialkyl
orthoformate in the presence of an acid catalyst. To
carry out this conversion, the lla-hydroxy substrate is
acidified by mixing with an acid such as, e.g., benzene
sulfonic acid hydrate or toluene sulfonic acid hydrate
and dissolved in a lower alcohol solvent, preferably
ethanol. A trialkyl orthoformate, preferably triethyl
orthoformate is introduced gradually over a period of 5
to 40 minutes while maintaining the mixture in the cold,
preferably at about 0°C to about 15°C. The mixture is
then warmed and the reaction carried out at a temperature
of between 20°C and about 60°C. Preferably the reaction
is carried out at 30~ to 50°C for 1 to 3 hours, then
heated to reflux for an additional period, typically 2 to
6 hours, to complete the reaction. Reaction mixture is
cooled, preferably to 0° to 15°, preferably about 5°C,
and the solvent removed under vacuum.
Using the same reaction scheme as described in
Scheme 3, above, for the conversion of the compound of
Formula XX to the compound of Formula XVII, a 17-
spirolactone moiety of Formula XXXIII is introduced into
CA 02550897 1997-12-11
136
the compound of Formula 101. For example, the Formula
101 substrate may be reacted with a sulfonium ylide in
the presence of a base such as an alkali metal hydroxide
in a suitable solvent such as DMSO, to produce an
intermediate corresponding to Formula 102:
Rs
HO,~~~
B
iA Bi
A
R~~O \ \
102
where -A-A-, R', R11, and -B-B- are as defined in Formula
101. The intermediate of Formula 102 is then reacted
with a malonic acid diester in the presence of an alkali
metal alkoxide to form the five membered spirolactone
ring and produce the intermediate of Formula 103
0
R~ O COpR~2
H 0,~~~ _ _
B
A Bi
A
R~~O \ \
103
where -A-A-, R3, R11 and -B-B- are as defined in Formula
102, and R12 is a C1 to C4 alkyl, preferably ethyl.
Finally, the compound of Formula 103 in a suitable
solvent, such as dimethylformamide, is subjected to heat
in the presence of an alkali metal halide, splitting off
the alkoxycarbonyl moiety and producing the intermediate
of Formula 104:
CA 02550897 1997-12-11
137
0
R3
O
H 0,~~~ _ _
B
AiA B
R~~O \ ~
104
where again -A-A-, R', R11 and -H-B- are as defined in
Formula 102.
Next the 3,4-enol ether compound 104 is
converted to the compound of Formula XXIII, i.e:, the
compound of Formula VIII in which Re and R9 together form
the moiety of Formula XXXIII. This oxidation step is
carried out in essentially the same manner as the
oxidation step for conversion of the compound of Formula
XXIV to the intermediate of Formula XXIII in the
synthesis of Scheme 4. Direct oxidation can be effected
using a reagent such as 2,3-dichloro-5,6-dicyano-1,4-
benzoquinone (DDQ) or tetrachlorobenzoquinone
(chloranil), or preferably a two stage oxidation is
effected by first brominating, e.g., with an N-halo
brominating agent such as N-bromosuccinamide (NBS) or
1,3-dibromo-5,5-dimethyl hydantoin (DBDMH) and then
dehydrobrominating with a base, for example with DABCO in
the presence of Liar and heat. Where NBS is used for
bromination, an acid must also be employed to convert 3-
enol ether to the enone. DBDMH, an ionic rather than
free radical bromination reagent, is effective by itself
for bromination and conversion of the enol ether to the
enone.
The compound of Formula VIII is then converted
to epoxymexrenone or other compound of Formula I by the
steps described hereinabove for Scheme 1.
Each of the intermediates of Formulae 101, 102,
103 and 104 is a novel compound having substantial value
CA 02550897 1997-12-11
138
as an intermediate for epoxymexrenone or other compounds
of Formulae IA and I. In each of the compounds of
Formulae 101, 102, 103 and 104, -A-A- and -B-B- are
preferably -CHZ-CHz- and R3 is hydrogen, lower alkyl or
lower alkoxy. Preferably, R' is hydrogen. Most
preferably, the compound of Formula 101 is 3-ethoxy-lla-
hydroxyandrast-3,5-dien-17-one, the compound of Formula
102 is 3-ethoxyspiro[androst-3,5-diene-17!3,2'-oxiran]-
11a-ol, the compound of Formula 103 is ethyl hydrogen 3-
ethoxy-lla-17a-dihydroxypregna-3,5-diene-21;21-
dicarboxylate, gamma-lactone, and the compound of Formula
104 is 3-ethoxy-lla-17a-dihydroxypregna-3,5-diene-21-
carboxylic acid, gamma-lactone.
In a particularly preferred embodiment, the
overall process of Scheme 6 proceeds as follows:
CA 02550897 1997-12-11
139
D 0 0
HO,~~ HO,,~~
CH(OR)3
11-hvdroxylaUOn / \
0 ~ 0 acid catalyst ~ R 0
Bioconrerslon (101)
11-a-Hydroxyandrostendlone
Androslendione (AD) (CH3)35~X-
KOH, DMSO
0 0
0 0 COzEI Ow
HO,~ nul NaCI. DMF HO~~~, nn O
CH2(COZEI)z
heap t
NaOEt
\ \ (104) p0 \ \ (103) pp \ ~ (102)
RO
3 melhod5
possible
0 O
0
HO,, ~ii~~l Technology
snown m Scneme t
0
tt-a-Hyaroxytanrenone EpoxYmexrenone
It is hypothesized that epoxymexrenone and
other compounds corresponding to Formula I likewise can
be prepared from ll~i-hydroxyandrostendione or other
compounds of Formula XXXV which have been 11Q-
hydroxylated. In other words, epoxymexrenone and other
compounds corresponding to Formula I can be prepared in
accordance with the general process set forth in Scheme 6
using either an a-hydroxylated substrate of Formula XXXV
or the corresponding ~3-hydroxylated substrate.
Scheme 7
Scheme 7 provides for the synthesis of
epoxymexrenone and other compounds of Formula I using a
CA 02550897 1997-12-11
140
starting substrate comprising f~-sitosterol, cholesterol,
stigmasterol or other compound of Formula XXXVII
,.
R t ti
D
'R t a
H XXXVII
where -A-A-, R3, and -H-H- are as defined in Formula XIII;
D-D is -CH2-CH2- or -CH=CH-; and each of Rl', R~', R~s and
Ri6 is independently selected from among hydrogen or Cl to
C4 alkyl. R' is preferably hydrogen.
In the first step of the synthesis 11a-
hydroxyandrostendione or other compound of Formula XXXVI
is prepared by bioconversion of the compound of Formula
XXXVII. The bioconversion process is carried out
substantially in accordance with the method described
hereinabove for the lla-hydroxylation of canrenone (or
other substrate of Formula XIII).
In the synthesis lla-hydroxyandrostendione, 4-
androstene-3,17-dione is initially prepared by
bioconversion of the compound of Formula XXXVII. This
initial bioconversion may be carried out in the manner
described in U.S. patent 3,759,791, which is expressly
incorporated herein by reference. Thereafter , 4-
androstene-3,17-dione is converted to lla-
hydroxyandrostenedione substantially in accordance with
the method described hereinabove for the lla-
hydroxylation of canrenone (or other substrate of Formula
XIII).
The remainder of the synthesis of Scheme 7 is
identical to Scheme 6. In a particularly preferred
embodiment, the overall process of Scheme 7 proceeds as
follows:
CA 02550897 1997-12-11
141
0 0
HO~~~~ HO~~~~
Et
CH(OR)3
8loconversion / -----~
-~-~ 0 acrd catalyst RO
(101)
11~a~Hydroxyandrostendione
Sltosterol
(CH3)35~%
KOH, OM50
O
3 methoCS
possible
0
CO~Et 0'
Haft, OMF HO,~~~
Hz(COZEUZ
v
neat
aOEI
RO \ \ (tE2)
Technology
Shown In SCheme 1
11~a~Hydroxycanrenone Epoxymexrenone
It is hypothesized that epoxymexrenone and
other compounds corresponding to Formula I likewise can
be prepared in accordance with the general process set
S forth in Scheme 7 when the product of the bioconversion
of Q-sitosterol or other compounds of Formula XXXVIIi is
liQ-hydroxyandrostendione or other compounds of Formula
XXXV which have been ll~i-hydroxylated. In other words,
epoxymexrenone and other compounds corresponding to
Formula I can be prepared in accordance with the general
process set forth in Scheme 7 when~the bioconversion of
~i-sitosterol or other compounds of. Formula XXXVIII
results in the preparation of either an a-hydroxylated
substrate of Formula XXXV or the corresponding ~3-
hydroxylated substrate.
CA 02550897 1997-12-11
142
Scheme 8
A significant complication in the synthesis of
epoxymexrenone and related compounds is the need for
stereoselective introduction of an a-alkoxycarbonyl
substituent at the 7-carbon, without unwanted
modifications at other sites of the steroidal structure.
In accordance with the invention, it has been discovered
that an effective synthesis path for introduction of a
7a-alkoxycarbonyl substituent involves the following
steps: (i) initial cyanidation at the 7-carbon of the
steroid, (ii) hydrolysis of the 7-cyano steroid to form a
mixture of 7a-carboxylic acid and 7,Q-carboxylic acid
steroids, (iii) formation of a 5,7-lactose steroid from
the 7a-carboxylic acid steroid, and (iv) separation of
the 7(3-carboxylic acid steroid from the 5,7-lact.one
steroid. A base-mediated opening reaction of the 5,7-
lactone steroid with an alkylating reagent produces the
desired 7a-alkoxycarbonyl steroid.
Accordingly, the process of Scheme 8 is
generally directed to a process for the preparation of a
3-keto-7a-alkoxycarbonyl substituted o4~5-steroid
comprising reacting an alkylating reagent with a 3-keto-
4,5-dihydro-5,7-lactose steroid substrate in the presence
of a base. The lactose substrate is substituted with
keto at the 3-carbon, and further comprises the moiety:
'c~ s~ c~ m
o---~~
where C(5) represents the 5-carbon and C(7) represents
the 7-carbon of the steroid structure of the substrate.
Conversion of the 5,7-lactose to the 7a-alkoxycarbonyl is
preferably effected by reaction with an alkyl halide in
the presence of the base. The alkyl halide reagent is
preferably an iodide, most preferably methyl iodide.
CA 02550897 1997-12-11
143
Further in accordance with the invention, an
advantageous process has been discovered for the
preparation of the 4,5-dihydro-5,7-lactone steroid
compound described above. In this process, a 3-keto-0°.s-
7a-cyano substituted steroid substrate is converted to
the 7-carboxylic acid, and the acid in-turn reacts with
the trialkyl orthoformate in an acidified lower alcohol
solvent to yield the 5,7-lactone. Reaction with
orthoformate esters also converts the 3-keto group to the
3-acyclic or cyclic ketal 5,7-lactone (the lactone is
understood to form first). Preferably, the 3-ketal 5,7-
lactone is a 3-dialkyl ketal 5,7-lactone. More
preferably, the alkyl moiety of the alcohol solvent is
the same as the alkyl moiety of the orthoformate alkoxy
groups (and most preferably all are methyl) because: the
alkoxy moieties of the ketal can derive either from the
orthoformate or the alcohol; mixed ketals are not
preferred and 3-dimethoxy is preferred. Where the ketal
is an ethylene ketal, the alkyl moiety of the alcohol
solvent need not be the same as the alkyl moiety of the
orthoformate alkoxy groups. The 3-ketal-5,7-lactone is
readily hydrolyzed to the 3-keto-5,7-lactone, a
crystalline compound which can be easily purified. Since
only the 7a-carboxylic acid undergoes the lactonization
reaction, complete stereospecificity is realized. The
7~-acid may then be removed from the reaction mixture in
the form of its salt, e.g., by treating the 7R-acid with
a mild base such as sodium bicarbonate.
The 7-cyano substrate for the formation of the
5,7-lactone can be prepared in a known manner. For
example, a substrate unsubstituted at the 7-carbon may be
reacted with a slight excess of cyanide ion, preferably
about 1.05 to about 1.25 equivalents per equivalent
substrate in a weakly acidic solution comprising a
water/DMSO solvent mixture. Preferably, the reaction
mixture includes a carboxylic acid, e.g., about one
CA 02550897 1997-12-11
144
equivalent acetic acid per equivalent substrate. Both
the 7a- and 713-CN isomers are formed with the 7a-isomer
as the major isomer. The 7a-cyano steroid may be
recovered in a conventional manner. Other methods known
to the art are useful in this ancillary preparation.
Generally in accordance with Scheme 8, the 5,7-
lactone may be formed from a 7-carboxy intermediate
(which itself is prepared by hydrolyzing a 7-cyano
intermediate) that is substituted at the 17-position with
either keto, Re or R9, where Re and R9 are as described
above, and having either an aliphatic, olefin, epoxide or
hydroxy substituted configuration at C-9 and C-11, i.e.,
R9 eo
p _R°o
R~ Reo E~
Rso I B
A E
E
I .B RieO
AAA E Bi _ ( aoa
R~eO p~ scheme 9)
~~O
cN XL ~ xu
R3 eo
R Rso
B
B
v = v _
0
~c XLII
where -A-A-, -B-B- and R3 are as defined above, RB° and R9°
are the same as R8 and R9, . or R8° and R9° together
constitute keto, and R18 is as described below regarding
Scheme 9, and -E-E- is selected from among
CA 02550897 1997-12-11
145
R21 R22
C- C-
23 ;CM- Cit=- III
e~9~~
R21
~C = C- ~C ~ CH~
e.g., ~ XLIV
R21 ~R24
OH
22 a - ~cH. cH. ~V
g..
0R24 R21
\I 1 off
C C-
Rz2 ~~-~H=. xLVI
, e.g.,
0 0
~c=cA$' - , usually, ~c=cN- XLVII
The compound of Formula XLII is then converted to the 7a-
alkoxy-carbonyl: .
0
pro
O
° XLII
R' Rto
Rio
E \
I a
AAA E Bi
° / ~~~~~~ XLVIII
CA 02550897 1997-12-11
146
In each of XL, XLI , XLI I and XLVI I I , Re° and R9° together
preferably comprise keto or
Y2
Y ~C( 1 7) mn( CHz) z - C ~ X ~I'T
/ \
where Y1, Yz, X and' C ( 17 ) are as def fined above , and most
preferably R°° and R9° together comprise
0
0
luiii ' XXXILI
R3 is preferably H, Rl is preferably methoxycarbonyl, and
-A-A- and -B-B- are each preferably -CHz-CHI-. It will be
understood that the reactions can also be carried out
with the 3-keto group protected by converting it to and
maintaining it in each ether or ketal form throughout the
reaction sequence. Alternative processes of Scheme 8
comprise use of various intermediates within the scope of
Formulae XLI and XLII as recited hereinabove..
Noting that the reagent for formation of the
5;7-lactone from the 3-keto-a°'S-7-carboxylic acid per
Scheme 8 is the trialkyl orthoformate, the same reagent
used in conversion of the lla-hydroxyandrostendione to
the 3-enol ether-3,5-diene-lla-hydroxy intermediate 101
of Scheme 6, it is believed that the path of the Scheme 8
reaction is dependent on substitution at C-7. Reaction
with orthoformate in the presence of H' forms an
intermediate carbonium ion having a carboxyl at C-7 and
its positive charge in equilibrium between C-3 and C-5.
Upon loss of the proton, the C-3 carbonium ion yields the
compound of Formula 101, while the C-5 carbonium ion
yields the lactone. With hydrogen at C-7, it is believed
that 3,5-dien-3-alkoxy (enol ether) is favored because of
the double bond conjugation. With the 7a-COa substituent
CA 02550897 1997-12-11
147
at C-7, the C-5 carbonium ion is captured by t he carboxy
and the 5,7-lactone is formed. At this point the 3-keto
group is preferentially converted to the ketal, thereby
driving the reaction to completion.
Preferred embodiments of Scheme 8 are described
in Schemes 9 and 10, infra.
Scheme 9
Scheme 9-begins with the same substrate as
Scheme 4, i.e., the compound of Formula XX. This
substrate is first oxidized to the compound of Formula B:
Rs
n
B
B
where -A-A-, R', and -B-B- are as defined in Formula XIII.
The oxidation reaction is conducted in accordance with
any of the reaction schemes described above for
conversion of the compound of Formula XXIV to the
intermediate of Formula XXIII in the synthesis of
Scheme 4. Using the methods described for Scheme 8; the
compound of Formula B is converted to the 7-cyano
intermediate of Formula C
R~
O
B
A '
Ai B
2 0 0 / . ~~''CN C
where -A-A-, R3, and -B-B- are as defined in Formula XIII.
Next, the compound of Formula C is converted to the 5,7-
lactone of Formula D:
CA 02550897 1997-12-11
148
Rs
R~~
a
R"p ~~
o D
where -A-A-, R3, and -B-H- are as defined in Formula XIII
and Rl' is Ci-C4 alkyl, using the trialkyl orthoformate
reagent utilized previously in Scheme 6. The 5,7-lactone
of Formula D is readily separated from the unreacted 7-i3-
COOH, e.g:, by removal of the acid via a bicarbonate
wash, thereby establishing the desired C-7
stereochemistry and impeding epimerization in subsequent
reactions that are conducted under basic conditions:
Esterification of the lactone per reaction with alkyl
halide, as described in Scheme 8, yields the enester
intermediate of Formula II.
Continuing the Scheme 9 synthesis, the compound .
of Formula D is converted to a compound of Formula II.
With the 3-keto group protected by having been converted
to the ketal, a 20-spiroxane group of Formula XXXIII is
selectively introduced at the 17-position in accordance
with the reaction scheme described above for Schemes 3
and 6, supra, thereby producing a compound of Formula E
0
R3
I 1,~~~~
's
~A ~ e~
A
R~~O
R~~o oho
E
Because the 3-ketone is protected, hydrolysis
conditions may be selected which are optimal for
CA 02550897 1997-12-11
149
attacking the 17-ketone without concern for the formation
of by-products through reaction at the 3-position. After
hydrolysis of the 3-ketal compound of Formula E to the 3-
keto group structure of Formula F
~ ~o F
the latter intermediate is reacted with alkyl iodide in
the presence of base, per the conversion of Scheme 8, to
produce the intermediate enester of Formula II. Finally,
the latter intermediate is converted to epoxymexrenone or
other compound of Formula I, using any of the methods
described above for Scheme 1.
Scheme 9 benefits not only from the control of
stereochemistry afforded by the 5,7-lactone intermediate,
but enjoys the further advantage of allowing for a wider
range of hydrolysis conditions without interference of
the i7-spirolactone.
Like the reactions for other synthesis schemes
of this invention, the reactions of Scheme 9 may be used
for conversion of substrates other than those
particularly described above. Thus, for example, the
conversion of 3-keto- or 3-ketal-7-cyano steroids to 3-
keto- or 3-ketal-5,7-lactone, or the conversifln of the 3-
keto- or 3-ketal-5,7-lactone to 7a-alkoxycarbonyl, may be
carried out on compounds substituted at the 17-carbon by
RB and R9 as defined above, or more particularly by a
substituent of Formula:
CA 02550897 1997-12-11
150
Y2
t
Y~C\17) nm( CHp) q ~ C ~ X
XXXIV
where X, Y1 and Y~ are as defined above and C (17)
indicates the l7-carbon. However, important advantages
are realized, especially in process economics, by use of
the specific reaction sequence using 17-keto substrates
and following the specific reaction scheme described
above for introduction of 17-spirolactone and 7a-
alkoxycarbonyl into a 3-keto-X9.11 steroid.
The lactones of Formula D, E, and F are novel
compounds which are useful in the preparation of
epoxymexrenone and other compounds of Formula I and IA in
accordance with the synthesis of Scheme 9. In these
compounds -A-A- and -B-B- are preferably -CH2-CH2- and R3
is hydrogen, lower alkyl or lower alkoxy. Most
preferably the compound of Formula D is where R1' is
methoxy.
In a particularly preferred embodiment, the
overall process of Scheme 9 proceeds as follows:
CA 02550897 1997-12-11
151
0 O
(A] ~8J
0 0.
R
CD] ~\0 CC]
1. 17-l8ctone
2 . B/~Me 1 /~0
J~~/ 0
0
---
~~~~~COzMe
Scheme 10
Scheme 10 is the same as Scheme 9 through the
formation of the 7-cyano intermediate of Formula C. In
the next step of Scheme 10, 7-cyano steroid is reacted
with trialkyl orthoformate in an alkanol solvent,
preferably trimethyT orthoformate in methanol, to
simultaneously protect the 3-keto and 17-keto groups, by
converting the former to the enol ether and the latter to
the ketal. Thereafter the 7-cyano group is reduced to
7-formyl, e.g., by reaction with a dialkyl aluminum
CA 02550897 1997-12-11
152
hydride, preferably diisobutyl aluminum hydride, thereby
producing a compound of Formula 203:
R' ~s
~ ~R -OR~e
~B
AiA ( Hi
R"o ~ ~ ~'''cHO 2 03
where -A-A-, R', and -H-H- are as defined in Formula XIII,
and R'8 is Cl-C, alkyl. . Prior protection of the keto
groups, as described above, prevents their reduction by
the dialkyl aluminum hydride. The intermediate of
Formula 203 is next reacted with dilute aqueous acid to
selectively hydrolyze the 17-ketal, in the. presence of
excess alcohol (R190H), producing the intermediate of
Formula 204:
R~
n
B
Rti
R " O O---r ON
~H
[204]
where Rl9 is selected from among lower alkyl (preferably
C1 to C,) , or the R1' groups at the 3-position forming a
cyclic O,O-oxyalkyleneoxy substituent at the 3-carbon.
The hemiacetal [204] is further protected by treatment
with alkanol (R2°OH) in the presence of non-aqueous acid
to produce the intermediate of Formula 205:
CA 02550897 1997-12-11
153
R~
R~~
R..O ~OR~..
''''~~H' 12 0 5 ]
where -A-A- , -B-B- , R' and Rl' are as defined above , and
Rz° is Cl to C, alkyl. The 17-spirolactone moiety can then
be introduced in accordance with the reaction steps
described above for Schemes 3 and 6, thus proceeding
through the sequence outlined below:
9 s
R O R 01
\B ~ \B .
Ai A Bi Ai A 8
R~pO REDO
R"O O--rOR2° R~sO O~ORZO
~H 1205] -j ~H 1206]
0
R3
CO2 R25
AiA Bi
Rm0
R~ 00 O ~ OR2o
1207] -~
CA 02550897 1997-12-11
154
o
R»
R
[208]
wherein -A-A-, -B-H-, R3; R19, and R=° are as defined above
and RZS is Cl to C9 alkyl.
Thereafter the 3-position is deprotected by
conventional hydrolysis to reintroduce the 3-keto group
and 5,7-hemiacetal, producing the further intermediate
corresponding to Formula 209:
0
O---r OH
H [209]
where -A-A-, -B-B- and R3 are as defined above. Next, a
l0 9,11 epoxide moiety is introduced in accordance with any
of the methods described above for conversion of the
compounds of Formula II to the compounds of Formula I.
Under the oxidizing conditions of the epoxidation
reaction, the hemiacetal partially converts to the 5,7-
iactone, thereby producing a further intermediate
corresponding to Formula 211
CA 02550897 1997-12-11
155
0
R3
B
[211]
where -A-A-, -H-H- and R' are as defined above. Any
remaining 9,11-epoxy-5,7-hemiacetal intermediate reaction
product of Formula 210:
0
R3
O
ii
~~O 'B
A v~ i
Ai B
O
O---T OH
~H [210]
wherein -A-A-, -H-H- and R3 are as defined, is readily
oxidized by conventional means to the compound of Formula
211. Finally, the intermediate of Formula 211 is
converted to epoxymexrenone or other compound of Formula
I using the method described in Scheme 8 for the
conversion of the 5,7-lactone to the 7a-alkoxycarbonyl
compound. Thus, overall, Scheme 10 proceeds as follows,
it being understood that at least the following steps may
be carried out in situ without recovery of the
intermediate. Overall, the synthesis of Scheme 10
proceeds as follows:
CA 02550897 1997-12-11
156
R3 0 R3 OR~OR18
Protect
retJuce
0 ~ ~~°CN R,eO ~ ~ ~4~CN
RIB
[ 201] R3 0 [ 202] R3 0
OR1e
R0~9
R19 OOH R~e \ ~~~~CHO C 203]
H
[ 204]
R9
O
Reprotect
ROt a
Depr of eot
Rya __ _ t!
O~OR~ a RO
[ 205]
R t a v----t ~ o
O [ 208J
R
~~~ O
v
~ Epoxldetlon
O ~ ~ OH
OOH [ 209]
[ 21 0]
oxldlzs
O
O
~~~0
Eplerenons
O
O
[ 211] O
As in the case of Scheme 9, the reactions
described above for Scheme 10 offer important advantages,
CA 02550897 1997-12-11
157
especially with regard to process economics; but the
novel reactions of Scheme 10 also have more generic
application to substrates other than those particularly
described. For example, introduction of the 7-formyl
group into a 3-enol ether steroid, protection of the
resulting 7-formyl-D-5,6-3,4-enol ether, hydrolysis to
the 5,7-hemiacetal, and subsequent deprotection can be
conducted on steroids substituted at the 17-position by Re
and R9 as defined above, or more particularly by a
substituent of Formula:
YZ
t
Y ~C( 1 7) mn( CH2) 2 , ~ ~ x
\ ~Ig
where X, Yl YZ , and C ( 17 ) are as def fined above .
Alternative processes of Scheme 10 comprise use
of the various intermediates within the scope of Formulae
A203 through A210, respectively, hereinabove. Each of
the intermediates of Formulae A203 through A211 is a
novel compound which is useful in the preparation of
epoxymexrenone and other compounds of Formula I and IA in
accordance with the synthesis of Scheme 10.
In a particularly preferred embodiment, the
overall process of Scheme 10 proceeds as follows:
CA 02550897 1997-12-11
158
0 0 0
w. o ~ ~ ~ o ~ ~ ~ c ~ ''~~cH
t w1 l s1 ( ~1
~. weaa
:. RotWw
0
O RO
\'\~OR
1. Laeloolsatlon
2. D.prot.et I 1. Nydrolysb
9. Epotck.
4. oal0b. - 2. R.proHet
R RO ~ ~ '~~iCHO
O~O RO O-T-OR ( D'
~H
T 11G
W.i
O
From the several schemes that are illustrated
above, it will be understood that the reaction steps
selected for use in the processes of the invention
provide substantial flexibility in the manufacture of
epoxymexrenone and related compounds. The key features
include, inter alias (a) bioconversion of a substrate
such as canrenone, androstendione, or f3-sitosterol to an lla-
or 9a-hydroxy derivative (with simultaneous conversion
of fS-sitosterol to a 17-keto structure; (b) introduction
of the 9,11 double bond by dehydration of a compound
containing either an 11a- or 9a-hydroxy group, followed
by introduction of the epoxy group by oxidation of the
9, 11 double bond; (c) attachment of a 7cx-alkoxycarbonyl
by formation of the enamine, hydrolysis of the enamine to
the diketone, and reaction of the diketone with an alkali
metal alkoxide; (d) formation of the 20-spiroxane ring at
CA 02550897 1997-12-11
159
the 17 position; (e) formation of the 5,7-lactone, and
esterification of the lactone to the 7-alkoxycarbonyl;
(f) protection of the 3-ketone by conversion to 3-enol
ether or 3-ketal during various of the conversions at
other positions (including formation of the 20-spiroxane
ring at the 17-position. With few limitations, these
four component process elements (b) to (d) can be
conducted in almost any sequence. Process elements (e)
and (f) offer comparable flexibility. They provide a
route to epoxymexrenone and other compounds of Formula I
which are much simplified as compared to the process of
U.S. patent 4,559,332. Moreover, they provide important
benefits in productivity and yield.
In the descriptions of the reaction schemes. as
set forth above, recovery, isolation and purification of
reaction products can generally be carried out by methods
well known to those skilled in the art. Except where
otherwise indicated, conditions, solvents, and reagents
are either conventional, not narrowly critical, or both.
However, certain of the specific procedures as
particularly described above provide advantages which
contribute to the favorable overall yield and/or
productivity of the various process steps and process
schemes, and/or to high quality of the intermediates and
ultimate 9,11-epoxy steroid products.
The utility of 20-Spiroxane compounds produced
in accordance with the invention is described in Grob
U.S. patent 4,559,332.
20-Spiroxane compounds produced in accordance
with the invention are distinguished by favorable
biological properties and are, therefore, valuable
pharmaceutical active ingredients. For example, they
have a strong aldosterone-antagonistic action in that
they reduce and normalize unduly high sodium retention
and potassium excretion caused by aldosterone. They
CA 02550897 1997-12-11
160
therefore have, as potassium-saving diuretics, an
important therapeutic application,~for example in the
treatment of hypertension, cardiac insufficiency or
cirrhosis of the liver.
20-Spiroxane derivatives having an aldosterone-
antagonistic action are known, cf., for example, Fieser
and Fieser: Steroids; page 708 (Reinhold Publ. Corp., New
York, 1959) and British Patent Specification No.
1,041,534; also known are analogously active 17~i-hydroxy-
21-carboxylic acids and their salts, cf., for example,
U.S. Pat. No. 3,849,404. Compounds of this kind that
have hitherto been used in therapy, however, have a
considerable disadvantage in that they always possess a
certain sexual-specific activity which has troublesome
consequences sooner or later in the customary long-term
therapy. Especially undesirable are the troublesome
effects that can be attributed to the anti-androgenic
activity of the known anti-aldosterone preparations.
The methods, processes and compositions of the
invention, and the conditions and reagents used therein,
are further described in the following examples.
Example 1
Slants were prepared with a growth medium as
set forth in Table 1
2 5 TABLE 1 - Y P D A
(medium for slants and plates)
yeast extract 20 g
peptone 20 g
glucose 20 g
agar ' 20 g
distilled water, q.s. to 1'000 ml
-pH as is 6.7
-adjust at pH 5 with H3P04 10~
w/v
CA 02550897 1997-12-11
161
Distribute
-for slants:
7.5 ml in 180 x 18 mm tubes
-for plates (10 cm of ~)
25 ml in 200 x 20 mm tubes
-sterilize at I20°C for 20
minutes
-pH after sterilization:5
To produce first generation cultures, a colony of
Aspergillus ochraceus was suspended in distilled water (2
ml) in a test tube; and 0.15 ml aliquots of this
suspension applied to each of the slants that had been
prepared as described above. The slants were incubated
for seven days at 25°C, after which the appearance of the
surface culture was that of a white cottony mycelium.
The reverse was pigmented in orange in the lower part, in
yellow-orange in the upper part.
The first generation slant cultures were
suspended in a sterile solution (4 ml) containing Tween
80 nonionic surfactant (3% by weight), and 0.15 ml
aliquots of this suspension were used to inoculate second
generation slants that had been prepared with the growth
medium set forth in Table 2
TABLE 2
(for second generation and routine
slants)
malt extract 20 g
peptone 1 g
glucose 20 g
agar 20 g
distilled water q.s. to 1000 ml
-pH as is 5.3
-distribute in tubes (180 x
18 mm) ml 7.5
-sterilize at 120C for 20
minutes
CA 02550897 1997-12-11
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The second generation slants were incubated for l0 days
at 25°C, producing a heavy mass of golden-colored spores;
reverse pigmented in brown orange.
A protective medium was prepared having the
composition set forth in Table 3.
TABLE 3 - PRO TECTIVE MEDIUM
Skim milk 10 g
distilled water 100 ml
In a 25o ml flask
containing 100 ml
of distilled water
at 50C, add skim
milk. Sterilize at
120C for 15
minutes. Cool at
33C and use before
II the day is over
Cultures from five of the second generation slants were
suspended in the protective solution (15 ml) in a 100 ml
flask. The suspension was distributed in aliquots (0.5
ml each) among 100x10 mm tubes for lyophilization: These
were pre-frozen at -70° to -80°C in an acetone/dry ice
bath for 20 minutes, then transferred immediately to a
drying room pre-cooled to -40° to -50°C. The pre-frozen
aliquots were lyophilized at a residual pressure of 50 ~c
Hg and <-30°C: At the end of the lyophilization, two to
three granules of sterile silica gel were added to each
tube with moisture indicator and flame seal.
To obtain mother culture slants suitable for
3o industrial scale fermentation, a single aliquot of
lyophilized culture, which had been prepared in the
manner described above, was suspended in distilled water
(1 ml) and 0.15 ml aliquots of the suspension were used
to inoculate slants that had been provided with a growth
medium having the composition set forth in Table 2. The
CA 02550897 1997-12-11
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mother slants were incubated for seven days at 25°C. At
the end of incubation, the culture developed on the
slants was preserved at 4°C.
To prepare a routine slant culture, the culture
from a mother slant was suspended in a sterile solution
(4 ml ) containing Tween 80 ( 3 % by weight ) and the
resulting suspension distributed in 0.15 ml. aliquots
among slants which had been coated with the growth medium
described in Table 2. The routine slant cultures may be
used to inoculate the primary seed flasks for laboratory
or industrial fermentations.
To prepare a primary seed flask culture, the
culture from a routine slant, which had been prepared as
described above, was removed and suspended in a solution
(10 ml) containing Tween 80 (3% by weight). A 0.1
aliquot of the resulting suspension was introduced into a
500 ml baffled flask containing a growth medium having
the composition set forth in Table 4.
TABLE 4
(for primary and transformation
flask
culture and round bottomed flask)
glucose 20 g
peptone 20 g
yeast autolysate 20 g
distilled water q.s to
-pH as is 5.2
-adjust at pH 5.8 with NaOH
20%
-distribute in 500 ml baffled
flask 100 ml
-distribute in 2000 ml round
bottomed flasks (3 baffles)
500 ml
-sterilize 120C x 20 min.
-pH after sterilization
about 5.7
The seed flask was incubated on a rotating shaker (200
rpm, 5 cm displacement) for 24 hours at 28°C, thereby
CA 02550897 1997-12-11
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producing a culture in the form of pellet-like mycelia
having diameters of 3 to 4 mm. On microscopic
observation, the seed culture was found to be a pure
culture, with synnematic growth, with big hyphae and well
twisted. The pH of the suspension was 5.4 to 5.6. PMV
was 5 to 8% as determined by centrifugation (3 OOO rpm x 5
min . ) .
A transformation flask culture was prepared by
inoculating a growth medium (100 ml) having the
composition set forth Table 4 in a second 500 ml shaker
flask with biomass (1 ml) from the seed culture flask.
The resulting mixture was incubated on a rotating shaker
(200 rpm, 5 cm displacement) for 18 hours at 2 8°C. The
culture was examined and found to comprise pellet like
mycelia with a 3-4 mm diameter. On microscopic
examination, the culture was determined to be a pure
culture, with synnematic and filamentous growth in which
the apical cells were full of cytoplasm and the olden
cells were little vacuolated. The pH o~ the culture
suspension was 5 to 5.2 and the PMV was determined by
centrifugation to be between 10% and 15%. Accordingly,
the culture was deemed suitable for transformation of
canrenone to lla-hydroxycanrenone.
Canrenone (1 g) was micronized to about ~5 ~C and
suspended in sterile water (20 ml). To this suspension
were added: a 40% (w/v) sterile glucose solution; a 16%
(w/v) sterile solution of autolyzed yeast; and a sterile
antibiotic solution; all in the proportions indicated for
0 hours reaction time in Table 5. The antibiotic
solution had been prepared by dissolving kanamicyn
sulfate (40 mg), tetracycline HC1 (40 mg) and cefalexin
(200 mg) in water (100 ml). The steroid suspension,
glucose solution, and autolyzed yeast solution were added
gradually to the culture contained in the shaker flask.
CA 02550897 1997-12-11
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TABLE 5
Indicative
Additions
of Steroid
and Solutions
(additives
and antibiotics)
in the
Course
of Bioconversion
of Canrenone
in Shake
Flask
Reaction Steroid glucose yeast anti-
Suspension
time solution auto- biotic
hours ml approx. ml lised solution
mg. sol. ml
ml .
0 1 50 1 0.5 1
8 2 100 2 1
24 2 100 1 0.5 1
32 5 250 2 1
48 2 100 1 0.5 1
56 5 250 2 1
72 3 150 1 0.5 1
90
As reaction proceeded, the reaction mixture was
periodically analyzed to determine glucose content, and
by thin layer chromatography to determine conversion to
lla-hydroxycanrenone. Additional canrenone substrate and
nutrients were added to the fermentation reaction mixture
during the reaction at rates controlled to maintain the
glucose content in the range of about 0.1% by weight.
The addition schedule for steroid suspension, glucose
solution, autolyzed yeast solution and antibiotic
solution is set forth in Table 5. The transformation
reaction continued for 96 hours at 25°C on a rotary
shaker (200 rpm and 5 cm displacement). The pH ranged
between 4.5 and 6 during the fermentation. Whenever the
PMV rose to or above 60%, a 10 ml portion of broth
culture was withdrawn and replaced with 10 ml distilled
water. The disappearance of canrenone and appearance of
lla-hydroxycanrenone were monitored during the reaction
by sampling the broth at intervals of 4, 7, 23, 31, 47,
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55, 71, 80, and 96 hours after the start of the
fermentation cycle, and analyzing the sample by TLC. The
progress of the reaction as determined from these samples
is set forth in Table 6
TABLE 6
Time Course
of Bioconversion
of Canrenone
in Shake
Flask
Time Transformation Ratio
hours Canrenone Rf. llahydroxy
Canrenone
RF. - 0.81 RF. -
0.29
0 100 0.0
4 50 50
7 20 80
23 20 80
31 30 70
47 20 80
55 30 70
71 25 75
80 15 85
96 --10 -90
2 0 Exams 1 a 2
A primary seed flask culture was prepared in
the manner described in Example 1. A nutrient mixture
was prepared having the composition set forth in Table 7
TABLE 7
For Transformation Culture
in l0 1 glass fermenter
quantity g/1
glucose 80 g . 20
peptone
80 g 20
yeast autolyzed 80 g 20
antifoam SAG 471 0.5 g
CA 02550897 1997-12-11
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deionized water q.s. to 4 1
-sterilize the empty
fermenter for 30
minutes at 130°C
-load it with 3 1 of
deionized water,
heat at 40°C
-add while stirring
the components of
' 10 the medium
-stir for 15 minutes,
bring to volume of
3.9 1
-pH as is 5.1
-adjust of 5.8 with
NaOH 20~ w/v
-sterilize at 120°C
x 20 minutes
-pH after
sterilization 5.5
-5.7
An initial charge of this nutrient mixture (4L) was
introduced into a transformation fermenter of 10 L
geometric volume. The fermenter was of cylindrical
configuration with a height to diameter ratio of 2.58.
It was provided with a 400 rpm turbine agitator having
two No. 2 disk wheels with 6 blades each. The external
diameter of the impellers was 80 mm, each of the blades
was 25 mm in radial dimension and 30 mm high, the upper
wheel was positioned 280 mm below the top of the vessel,
the lower wheel was 365 mm below the top, and baffles for
the vessel were 210 mm high and extended radially
inwardly 25 mm from the interior vertical wall of the
vessel.
Seed culture t40 ml) was mixed with the
nutrient charge in the fermenter, and a transformation
culture established by incubation for 22 hours at 28°C,
and an aeration rate of 0.5 1/1-min. at a pressure of 0.5
kg/cm2. At 22 hours, the PMV of the culture was 20-25%
and the pH 5 to 5.2.
CA 02550897 1997-12-11
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A suspension was prepared comprising canrenone
(80 g) in sterile water (400 ml), and a 10 ml portion
added to the mixture in the transformation ferrnenter. At
the same time a 40% (w/v) sterile glucose solution, a 16%
(w/v) sterile solution of autolyzed yeast, and a sterile
antibiotic solution were added in the proportions
indicated in Table 8 at 0 hours reaction time: The
antibiotic solution was prepared in the manner described
in Example 1.
I
TABLE 8
Indicative
Additions
of Steroid
and Solutions
(additives
and antibiotics)
in the
Course
of Bioconversion
of Canrenone
in
10 1 Glass
Fermenter
Reaction Steroid glucose yeast anti-
time Suspension solution autolyzed biotic
hours ml approx ml solution solution
gr ml ~ ml
0 10 4 25 12.5 40
4 25 12.5
8 10 4 25 12.5
12 25 12.5
16 10 4 25 12.5
20 25 12.5
24 10 4 25 12.5 40
28 10 4 25 12.5
32 12.5 5 25 12.5 I
36 12.5 5 25 12.5
40 12.5 5 25 12.5
44 12.5 5 25 12.5
48 12.5 5 25 12.5 40
52 12.5 5 25 12.5
56 12.5 5 25 12.5
60 12.5 5 25 12.5
64 12.5 5 25 12.5
CA 02550897 1997-12-11
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68 12.5 5 25 12.5
72 12.5 5 25 12.5 40
76 12.5 5 25 12.5 i
80
84
88
As reaction proceeded, the reaction mixture was
periodically analyzed to determine glucose content; and
by thin layer chromatography to determine conversion to
ila-hydroxycanrenone. Based on TLC analysis of reaction
broth samples as described hereinbelow, additional
canrenone was added to the reaction mixture as canrenone
substrate was consumed. Glucose levels were also
monitored and, whenever glucose concentration dropped to
about 0.05% by weight or below, supplemental glucose
solution was added to bring the concentration up to about
0.25% by weight. Nutrients and antibiotics were also
added at discrete times during the reaction cycle. The
addition schedule for steroid suspension, glucose
solution, autolyzed yeast solution and antibiotic
solution is set forth in Table 8. The transformation
reaction continued for 90 hours at an aeration rate of
0.5 vol. air per vol. liquid per minute (vvm) at a
positive head pressure of 0.3 kg/cm2. The temperature was
maintained at 28°C until PVM reached 45%, then decreased
to 26°C and maintained at that temperature as PVM grew
from 45% to 60%, and thereafter controlled at 24°C.' The
initial agitation rate was 400 rpm, increasing to 700 rpm
after 40 hours. The pH was maintained at between 4.7 and
5.3 by additions of 2M orthophosphoric acid or 2M NaOH,
as indicated. Foaming was controlled by adding a few
drops of Antifoam SAG 471 as foam developed. The
disappearance of canrenone and appearance of 11a-
CA 02550897 1997-12-11
170
hydroxycanrenone were monitored at 4 hour intervals
during the reaction by TLC analysis of broth samples.
When most of the canrenone had disappeared from the
broth, additional increments were added.
After all canrenone additions had been made,
the reaction was terminated when TLC analysis showed that
the concentration of canrenone substrate relative to lla-
hydroxycanrenone product had dropped to about 5%.
At the conclusion of the reaction cycle, the
fermentation broth was filtered through cheese cloth for
separation of the mycelium from the liquid broth. The
mycelia fraction was resuspended in ethyl acetate using
about 65 volumes (5.2 liters) per gram canrenone charged
over the course of the reaction. The suspension of
mycelia in ethyl acetate was refluxed for one hour under
agitation, cooled to about 20°C, and filtered on a
Buchner. The mycelia cake was washed sequentially with
ethyl acetate (5 vol. per g canrenone charge; 0.4 L) and
deionized water (500 ml) to displace the ethyl acetate
extract from the cake. The filter cake was discarded.
The rich extract, solvent washing and water washing were
collected in a separator, then allowed to stand for 2
hours for phase separation.
The aqueous phase was then discarded and the
organic phase concentrated under vacuum to a residual
volume of 350 ml. The still bottoms were cooled to 15°C
and kept under agitation for about one hour. The
resulting suspension was filtered to remove the
crystalline product, and the filter cake was washed with
ethyl acetate (40 ml). After drying, the yield of 11~-
hydroxycanrenone was determined to be 60 g.
Example 3
A spore suspension was prepared from a routine
slant in the manner described in Example 1. In a 2000 ml
baffled round bottomed flask (3 baffles, each 50 mm x 3~
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mm), an aliquot (0.5 ml) of the spore suspension was
introduced into a nutrient solution (500 ml) having the
composition set forth in Table 4. The resulting mixture
was incubated in the flask for 24 hours at 25°C on an
alternating shaker (120 strokes per min.; displacement 5
cm), thereby producing a culture which, on microscopic
examination, was observed to appear as a pure culture
with hyphae well twisted. The pH of the culture was
between about 5.3 and 5.5, and the PMV (as determined by
centrifugation at 3000 rpm for 5 min.) was 8 to 10%.
Using the culture thus prepared, a seed culture
was prepared in a stainless steel fermenter of vertical
cylindrical configuration, having a geometric volume of
160 L and an aspect ratio of 2.31 (height = 985 mm;
diameter = 425 mm). The fermenter was provided with a
disk turbine type agitator having two wheels, each wheel
having six blades with an external diameter of 240 mm,
each blade having a radial dimension of 80 mm and a
height of 50 mm. The upper wheel was positioned at a
depth of 780 mm from the top of the fermenter, and the
second at a depth of 99S mm. Vertical baffles having a
height of 890 mm extended radially inwardly 40 mm from
the interior vertical wall of the fermenter. The
agitator was operated at 170 rpm. A nutrient mixture
(100 L) having the composition set forth in Table 9 was'
introduced into the fermenter, followed by a portion of
preinoculum (1 L) prepared as described above and having
a pH of 5.7.
TABLE 9
For Vegetative Culture
in 160 L
Fermenter About 8 L are
needed
to Seed Productive fermenter
Quantity g/L
glucose 2 kg 20
peptone 2 kg 20
yeast autolysed 2 kg 20
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antifoam SAG 471 0.010 Kg traces
deionized water q.s. to 100 L
-sterilize the empty
fermenter for 1 hour
at 130C
-load it with 6 L of
deionized water;
heat at 40C
-add while stirring
the components of
the medium
-stir for 15 minutes,
bring to volume of
95 L
-sterilization at
121C for 30 minutes
-post sterilization
pH is 5.7
-add sterile
deionized water
to 100 L
The inoculated mixture was incubated for 22 hours at. an
aeration rate of 0.5 L/L-min. at a head pressure of 0.5
kg/cm2. The temperature was controlled at 28°C until PMV
reached 25%, and then lowered to 25°C. The pH was
controlled in the range of 5.1 to 5.3. Growth of
mycelium volume is shown in Table l0, along with pH and
dissolved oxygen profiles of the seed culture reaction.
TABLE 10
Time Course for
Mycelial Growth
in
Seed Culture
Fermentation
Fermentation pH packed dissolved
period h mycelium oxygen %
volume (pmv)%
(3000
rpms5min)
0 5.7 0.1 100
4 5.7 0.1 100
8 5.7 0.1 12 3 85 5
12 5.7 0.1 15 3 72 5
16 5.5 0.1 25 5 40 5
CA 02550897 1997-12-11
173
20 . 5.4 0.1 30 5 35 5
22 5.3 0.1 33 S 30 5
24 5.2 0.1 35 5 25 5
Using the seed culture thus produced, a transformation
fermentation run was carried out in a vertical
cylindrical stainless steel fermenter having a diameter
of 1.02 m,w a height of 1.5 m and a geometric volume of
1.4 m3. The fermenter was provided with a turbine
agitator having two impellers, one positioned 867 cm
below the top of the reactor and the other positioned
1435 cm from the top. Each wheel was provided with six
blades, each 95 cm in radial dimension and 75 cm high.
Vertical baffles 1440 cm high extended radially inwardly
100 cm from the interior vertical wall of the reactor. A
nutrient mixture was prepared having the composition set
forth in Table 11
TABLE 11
For Bioconversion Culture
in 1000 L Fermenter
Quantity g/L
glucose 16 kg 23
peptone 16 kg 23
yeast autolysed 16 kg 23
antifoam SAG 471 0:080 Kg traces
CA 02550897 1997-12-11
174
deionized water q.s. to 700 L
-sterilize the empty
fermenter for l hour
at 130°C
-load it with 600 L
ofdeionized water;
heat at 40°C
-add while stirring
the components of
the medium
-stir for 15 minutes,
bring to volume of
650 L
-sterilization at
121°C for 30 minutes
-post sterilization
pH is 5.7
-add sterile
deionized water
to 700 L
An initial charge (700 L) of this nutrient mixture (pH =
5.7) was introduced into the fermenter, followed by the
seed inoculum of this example (7 L) prepared as described
above.
The nutrient mixture containing inoculum was
incubated for 24 hours at an aeration rate of 0.5L/L-min
at a head pressure of 0.5 kg/cmz. The temperature was
controlled at 28°C, and the agitation rate was 110 rpm.
Growth of mycelium volume is shown in Table 12, along
with pH and dissolved oxygen profiles of the seed culture
reaction.
TABLE 12
Time Course for
Mycelial Growth
in
Fermenter of
the Transformation
Culture
Fermentation pH packed dissolved
period h mycelium oxygen %
volume (pmv)
(3000 rpmx5
min)
0 5.6 0.2 100
4 5.5 0.2 100
CA 02550897 1997-12-11
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8 5.5 0.2 12 t 3 95 5
12 15 3 90 5
16 5.4 0.1 20 f 5 75 5
20 5.3 0.1 25 f 5 60 5
22 ~ 5.2 0.1 ~ 30 t 5 ~ 40 5
~
At the conclusion of the incubation, pelleting of the
mycelium was observed, but the pellets were generally
small and relatively loosely packed. Diffuse mycelium
was suspended in the broth. Final pH was 5.l to 5.3.
To the transformation culture thus produced was
added a suspension of canrenone (1.250 kg; micronized to
5 ~.) in sterile water (5 L)~. Sterile additive solution
and antibiotic solution were added in the proportions
indicated at reaction time 0 in Table 14. The
composition of the additive solution is set forth in
Table l3.
TABLE 13 ADDITIVE SOLUTION
(for transformative culture)
quantit
dextrose 40 Kg
yeast autolysate 8 Kg
antifoam SAG 471 0.010 Kg
CA 02550897 1997-12-11
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deionized water q.s. to 100 1
-sterilize a 150 1 empty
fermenter for 1 hour at
130°C
-load it with 70 1 of
deionized water; heat
at 40°C
-add while stirring the
components of "additive
solution"
-stir-for 30 minutes,
bring to volume of 95 1
-pH as is 4.9
-sterilize at 120°C
x 20 minutes
-pH after sterilization
about 5
Bioconversion was carried out for about 96 hours with
aeration at 0.5 L/L-min. at a head pressure of 0.5 kg/cm~
and a pH of ranging between 4.7 and 5.3, adjusted as
necessary by additions of~ 7 . 5 M NaOH or 4 M H3P0, . The
agitation rate was initially 100 rpm, increased to 165
rpm at 40 hours and 250 rpm at 64 hours. The initial
temperature was 28°C, lowered to 26°C when PMV reached
45%, and lowered to 24°C when PMV rose to 60%. SAG 471
in fine drops was added as necessary to control foaming.
Glucose levels in the fermentation were monitored at 4
hour intervals and, whenever the glucose concentration
fell below 1 gpl, an increment of sterile additive
solution (10 L) was added to the batch. Disappearance of
canrenone and appearance of lla-hydroxycanrenone were
also monitored during the reaction by HPLC. When at
least 90% of the initial canrenone charge had been
converted to lla-hydroxycanrenone, an increment of 1.250
kg canrenone was added. When 90% of the canrenone in
that increment was shown to have been converted, another
1.250 kg increment was introduced. Using the same
criterion further increments (1.250 kg apiece) were added
until the total reactor charge (20 kg) had been
CA 02550897 1997-12-11
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introduced. After the entire canrenone charge had been
delivered to the reactor, reaction was terminated when
the concentration of unreacted canrenone was 5% relative
to the amount of lIa-hydroxycanrenone produced. The
schedule for addition of canrenone, sterile additive
solution, and antibiotic solution is as shown in
Table 14.
TABLE 14
Additions
0 of the
Steroid
and Solutions
(additives
and antibiotics)
in the Course
of Hioconversion
of Canrenone
in Fermenter
I
Reaction C A N R Sterile anti- volume i
time E N O N additive biotic liters
5 hours E solution solution about
in suspension liters liters
Kg Progress
-ive Kg
0 I.250 1.25 10 8 ?00
4 10
8 1.250 2.5 10
I2 10
20 I6 1.250 10
20 10
24 1.250 5 10 8 800
28 1.250 10
32 1.250 10
25 36 1.250 10
40 1.250 10
44 1.250 10
48 1.250 12.5 10 8 900
52 1.250 10
30 56 1.250 10
60 1.250 10
64 1.250 10
68 1.250 10
72 1.250 20 10 8 1050
CA 02550897 1997-12-11
178
76 0
BO
84 -
88
92
Total
When bioconversion was complete, the mycelia
were separated from the broth by centrifugation in a
basket centrifuge. The filtrate was determined by FiPLC
to contain only 2% of the total quantity of lla-
hydroxycanrenone in the harvest broth, and was therefore
eliminated. The mycelia were suspended in ethyl acetate
(1000 L) in an extraction tank of 2 m' capacity. This
suspension was heated for one hour under agitation and
ethyl acetate reflux conditions, then cooled and
centrifuged in a basket centrifuge. The mycelia cake was
washed with ethyl acetate (200 L) and thereafter
discharged. The steroid rich solvent extract was allowed
to stand for one hour for separation of the water phase.
The water phase was extracted with a further amount of
ethyl acetate solvent (200 L) and then discarded. The
combined solvent phases were clarified by centrifugation
and placed in a concentrator (500 L geometric volume) and
concentrated under vacuum to a residual volume of 100 L.
In carrying out the evaporation, the initial charge to
the concentrator of combined extract and wash solutions
was 100 L, and this volume was kept constant by continual
or periodic additions of combined solution as solvent was
taken off. After the evaporation step was complete, the
3D still bottoms were cooled to 20°C and stirred for two
hours, then filtered on a Huchner filter. The
concentrator pot was washed with ethyl acetate (20 L) and
this wash solution was then used to wash the cake on the
CA 02550897 1997-12-11
179
filter. The product was dried under vacuum for 16 hours
at 50°C. Yield of lla-hydroxycanrenone was 14 kg.
Example 4
Lyophilized spores of Asperaillus ochraceus
NRRL 405 were suspended in a corn steep liquor growth
medium (2 ml) having the composition set forth in
Table 15:
_ I
TABLE 15 - Corn Steep Liquor Medium
(Growth Medium for Primary Seed Cultivation)
Corn steep liquor 30 g
Yeast extract 15 g
Ammonium phosphate 3 g
Monobasic
Glucose (charge after sterilization) 30 g
distilled water, q.s. to 1000 m1
pH as is: 4.6, adjust to pH 6.5 with
20~ NaOH, distribute 50 ml to 250 ml
Erlenmeyer flask sterilize 121C for
minutes.
20 The resulting suspension was used in an inoculum for the
propagation of spores on agar plates. Ten agar plates
were prepared, each bearing a solid glucose/yeast
extract/phosphate/agar growth medium having the
composition set forth in Table 16:
TABLE 16 - GYPA
(Glucose/Yeast Extract./Phosphate
Agar for Plates)
Glucose (charge after sterilization) 10 g
Yeast extract 2.5 g
3 0 KZHP04 3 g
Agar 20 g
distilled water, q.s. to 1000 ml
adjust pH to 6.5
sterilize 121C for 30 minutes
CA 02550897 1997-12-11
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A 0.2 ml aliquot of the suspension was transferred onto
the surface of each plate. The plates were incubated at
25°C for ten days, after which the spores from all the
plates were harvested into a sterile cryogenic protective
medium having the composition set forth in Table l7:
TABLE 17 - GYP/Glycerol
(Glucose/Yeast Extract/
Phosphate/Glycerol
medium for stock vials)
Glucose (charge after sterilization) 10 g
Yeast extract 2.5 g
KZFiPOq 3 g
Glycerol 20 g
Distilled water, q.s. to 1000 mL
Sterilize at 121C for 30 minutes
The resulting suspension was divided among twenty vials,
with one ml being transferred to each vial. These vials
constitute a master cell bank that can be drawn on to
produce working cell banks for use in generation of
inoculum for bioconversion of canrenone to lla-
hydroxycanrenone. The vials comprising the master cell
bank were stored in the vapor phase of a liquid nitrogen
freezer at -130°C.
To begin preparation of a working cell bank,
the spores from a single master cell bank vial were
resuspended in a sterile growth medium (1 ml) having the
composition set forth in Table 15. This suspension was
divided into ten 0.2 ml aliquots and each aliquot used to
inoculate an agar plate bearing a solid growth medium
having the composition set forth in Table 16. These
plates were incubated for ten days at 25°C. By the third
day of incubation, the underside of the growth medium was
brown-orange. At the end of the incubation there was
heavy production of golden colored spores. The spores
from each plate were harvested by the procedure described
CA 02550897 1997-12-11
181
hereinabove for the preparation of the master cell bank.
A total of one hundred vials was prepared, each
containing 1 ml of suspension. These vials constituted
the working cell bank. The working cell bank vials were
also preserved by storage in the vapor phase of a liquid
nitrogen freezer at -130°C.
Growth medium (50 ml) having the composition
set forth in Table 15 was charged to a 250 ml Erlenmeyer
flask. An aliquot (0.5 ml) of working cell suspension
was introduced into the flask and mixed with the growth
medium. The inoculated mixture was incubated for 24
hours at 25°C to produce a primary seed culture having a
percent packed mycelial volume of approximately 45%.
Upon visual inspection the culture was found to comprise
pellet-like mycelia of 1 to 2 mm diameter; and upon
microscopic observation it appeared as a pure culture.
Cultivation of a secondary seed culture was
initiated by introducing a growth medium having the
composition set forth in Table 15 into a 2.8 L Fernbach
flask, and inoculating the medium with a portion (10 ml)
of the primary seed culture of this example, the
preparation of which was as described above. The
inoculated mixture was incubated at 25°C for 24 hours on
a rotating shaker (200 rpm, 5 cm displacement). At the
end of the incubation, the culture exhibited the same
properties as described above for the primary seed
culture, and was suitable for use in a transformation
fermentation in which canrenone was bioconverted to lla-
hydroxycanrenone.
Transformation was conducted in a Braun ~
Biostat fermenter configured as follows:
Capacity: 15 liters with round bottom
Height: 53 cm
Diameter: 20 cm
3 5 Fi/D : 2 . 65
Impellers: 7.46 cm diameter, six paddles 2.2 x
1.4 cm each
CA 02550897 1997-12-11
182
Impeller spacing: 65.5, 14.5 and 25.5 cm from bottom
of tank
Baffles: four 1.9 x 48 cm
Sparger: 10.1 cm diameter, 21 holes --l mm
diameter
Temperature control: provided by means of an external
vessel jacket
Canrenone at a concentration of 20 g/L was suspended in
deionized water (4 L) and a portion (2 L) of growth
medium having the composition set forth in Table 18 was
added while the mixture in the fermenter was stirred at
300 rpm.
TABLE 18
(Growth medium for bioconversion
culture in 10 L fermenter)
Quantity Amount/L
glucose (charge after 160 g 20 g
sterilization)
peptone 160 g 20 g
yeast extract 160 g 20 g
antifoam SAF471 4:O m1 0.5 m1
Canrenone 160 g 20 g
deionized water q.s. to 7.5L
sterilize 121C for 30
minutes
The resulting suspension was stirred for 15 minutes,
after which the volume was brought up to 7.5 L with
additional deionized water. At this point the pH of the
suspension was adjusted from 5.2 to 6.5 by addition of
20% by weight NaOH solution, and the suspension was then
sterilized by heating at 121°C for 30 minutes in the
Braun E fermenter. The pH after sterilization was
6.3~0.2, and the final volume was 7.0 L. The sterilized
suspension was inoculated with a portion (0.5 L) of the
secondary seed culture of this example that has been
prepared as described above, and the volume brought up to
CA 02550897 1997-12-11
183
8.0 L by addition of 50% sterile glucose solution.
Fermentation was carried out at a temperature of 28°C
until the PMV reached 50%, then lowered to 26°C, and
further lowered to 24°C when PMV exceeded 50% in order to
maintain a consistent PMV below about 60%. Air was
introduced through the sparger at a rate of 0.5 vvm based
on initial liquid volume and the pressure in the
fermenter was maintained at 700 millibar gauge.
Agitation began at 60o rpm and was increased stepwise to
1000 rpm as needed to keep the dissolved oxygen content
above 30% by volume. Glucose concentration was
monitored. After the initial high glucose concentration
fell below 1% due to consumption by the fermentation
reaction, supplemental glucose was provided via a 50% by
weight sterile glucose solution to maintain the
concentration in the 0.05% to 1% range throughout the
remainder of the batch cycle. Prior to inoculation the
pH was 6.3~0.2. After the pH dropped to about 5.3 during-
the initial fermentation period, it was maintained in the
range of 5.5~0.2 for the remainder of the cycle by
addition of ammonium hydroxide. Foam was controlled by
adding a polyethylene glycol antifoam agent sold under
the trade designation SAG 471 by OSI Specialties, Inc.
Growth of the culture took place primarily
during the first 24 hours of the cycle, at which time the
PMV was about 40%, the pH was about 5.6 and the dissolved
oxygen content was about 50% by volume. Canrenone
conversion began even as the culture was growing:
Concentrations of canrenone and lla-hydroxycanrenone were
monitored during the bioconversion by analyzing daily
samples. Samples were extracted with hot ethyl acetate
and the resulting sample solution analyzed by TLC and
HPLC. The bioconversion was deemed complete when the
residual canrenone concentration was about 10% of the
initial concentration. The approximate conversion time
was 110 to 130 hours.
CA 02550897 1997-12-11
184
When bioconversion was complete, mycelial
biomass was separated from the broth by centrifugation.
The supernatant was extracted with an equal volume of
ethyl acetate, and the aqueous layer discarded. The
mycelial fraction was resuspended in ethyl acetate using
approximately 65 volumes per g canrenone charged to the
fermentation reactor. The mycelial suspension. was
refluxed for one hour under agitation, cooled to about
20°C, and filtered on a Buchner funnel. The mycelial
filter cake was washed twice with 5 volumes of ethyl
acetate per g of canrenone charged to the fermenter, and
then washed with deionized water (1 L) to displace the
residual ethyl acetate. The aqueous extract, rich
solvent, solvent washing and water washing were combined.
The remaining exhausted mycelial cake was either
discarded or extracted again, depending on analysis for
residual steroids therein. The combined liquid,phases
were allowed to settle for two hours. Thereafter, the
aqueous phase was separated and discarded, and the
organic phase concentrated under vacuum until the
residual volume was approximately 500 ml. The still
bottle was then cooled to about 15°C with slov~ agitation
for about one hour. The crystalline product was
recovered by filtration, and washed with chilled ethyl
acetate (100 ml) . Solvent was removed from tlZ.e crystals
by evaporation, and the crystalline product dried under
vacuum at 50°C.
Example 5
Lyophilized spores of AsperQillus ochraceus
ATCC 18500 were suspended in a corn steep liquor growth
medium (2 ml) as described in Example 4. Ten agar plates
were prepared, also in the manner of Example 4. The
plates were incubated and harvested as described in
Example 4 to provide a master cell bank. The vials
CA 02550897 1997-12-11
185
comprising the master cell bank were stored in the vapor
phase of a liquid nitrogen freezer at -130°C.
From a vial of the master cell bank, a working
cell bank was prepared as described in Example 4, and
stored in the nitrogen freezer at -130°C.
Growth medium (300 mL) having the composition
set forth in Table 19 was charged to a 2 L baffled flask.
An aliquot (3 mL) of working cell suspension was
introduced into the flask. The inoculated mixture was
incubated for 20 to 24 hours at 28°C on a rotating shaker
(200 rpm, 5 cm displacement) to produce a primary seed
culture having a percent packed mycelial volume of
approximately 45%. Upon visual inspection the culture
was found to comprise pellet like mycelia of 1 to 2 mm
diameter; and upon microscopic observation it appeared as
a pure culture.
TABLE 19
Growth medium for primary and
secondary seed cultivation
Amount/L
glucose (charge after 20 g
sterilization)
peptone 20 g
Yeast extract 20 g
distilled water q.s. to 1000 mL
sterilize 121C for 30 minutes
Cultivation of a secondary seed culture was
initiated by introducing 8L growth medium having the
composition set forth in Table 19 into a 14L glass
fermenter. Inoculate the fermenter with 160 mL to 204 mL
of the primary seed culture of this example. The
preparation of which was as described above.
CA 02550897 1997-12-11
186
The inoculated mixture was cultivated at 28°C
for 18-20 hours, 200 rmp agitation, aeration rate was 0.5
vvm. At the end of the propagation, the culture
exhibited the same properties as described above for the
primary seed.
Transformation was conducted in a 60L
fermenter, substantially in the manner described in
Example 4, except that the growth medium had the
composition set forth in Table 20, and the initial charge
of secondary seed culture was 350 mL to 700 mL.
Agitation rate was initially 200 rpm, but increased to
500 rpm as necessary to maintain dissolved oxygen above
10% by volume. The approximate bioconversion time for 20
g/L canrenone was 80 to 160 hours.
Table 20
Growth Medium for Hioconversion
Culture in 60 L Fermenter
Quantity Amount/L
glucose (charge after 17.5 g 0.5 g
sterilization)
peptone 17.5 g 0.5 g
yeast extract 17.5 g 0.5 g
Canrenone (charge as a 700 g 20 g
20% slurry in sterile
water)
deionized water, q.s.
to 35 L
sterilize 121C for 30
minutes
Example 6
Using a spore suspension from the working cel l
bank produced in accordance with the method described in
Example 4, primary and secondary seed cultures were
prepared, also substantially in the manner described in
Example 4. Using secondary seed culture produced in this
manner, two bioconversion runs were made in accordance
with a modified process of the type illustrated in Fig.
CA 02550897 1997-12-11
187
1, and two runs were made with the process illustrated in
Fig. 2. The transformation growth medium, canrenone
addition schedules, harvest times, and degrees of
conversion for these runs are set forth in Table 21. Run
R2A used a canrenone addition scheme based on the same
principle as Example 3, while run R2C modified the
Example 3 scheme by making only two additions of
canrenone, one at the beginning of the batch, and one
after 24 hours. In runs R2B and R2D, the entire
canrenone charge was introduced at the beginning of the
batch and the process generally carried in the manner
described in Example 4, except that the canrenone charge
was sterilized in a separate vessel before it was charged
to the fermenter and glucose was added as the batch
IS progressed. A blaring blender was used to reduce chunks
produced on sterilization. In runs R2A and R28,
canrenone was introduced into the batch in methanol
solution, in which respect these runs further differed
from the runs of Examples 3 and 4, respectively.
CA 02550897 1997-12-11
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CA 02550897 1997-12-11
189
In runs R2A and R2B, the methanol concentration
accumulated to about 6.0% in the fermentation beer, which
was found to be inhibitory to the growth of culture and
bioconversion. However, based on the results of these
runs, it was concluded that methanol or other water-
miscible solvent could serve effectively at lower
concentrations to increase the canrenone charge and
provide canrenone as a fine particle precipitate
providing a large interfacial area for supply of
canrenone to the subject to the reaction.
Canrenone proved stable at sterilization
temperature (121°C) but aggregated into chunks. A blaring
blender was employed to crush the lumps into fine
particles, which were successfully converted to product.
Example 7
Using a spore suspension from the working cell
bank produced in accordance with the method described in
Example 4, primary and secondary seed cultures were
prepared, also substantially in the manner described in
Example 4. The description and results of Example 7 are
shown in Table 22. Using secondary seed culture produced
in this manner, one bioconversion (R3C) was carried out
substantially as described in Example 3, and three
bioconversions were carried out in accordance with the
process generally described in Example 5. In the latter
three runs (R3A, R3B and R3D), canrenone was sterilized
in a portable tank, together with the growth medium
except for glucose. Glucose was aseptically fed from
another tank. The sterilized canrenone suspension was
introduced into the fermenter either before inoculation
or during the early stage of bioconversion. In run R3B,
supplemental sterile canrenone and growth medium was
introduced at 46.5 hours. Lumps of canrenone formed on
sterilization were delumped through a blaring blender
thus producing a fine particulate suspension entering the
CA 02550897 1997-12-11
190
fermenter. The transformation growth media, canrenone
addition schedules, nutrient addition schedules, harvest
times, and degrees of conversion for these runs are set
forth in Tables 22 and 23.
CA 02550897 1997-12-11
191
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CA 02550897 1997-12-11
193
Due to filamentous growth, a highly viscous fermenter
broth was seen in all four of the runs of this Example.
To overcome obstacles which high viscosity created with
respect to aeration, mixing, pH control and temperature
control, the aeration rate and agitation speed were
increased during these runs. Conversions proceeded
satisfactorily under the more severe conditions, but a
dense cake formed above the liquid broth surface. Some
unreacted canrenone was carried out of the broth by this
cake.
Example 8
The description and results of Example 8 are
summarized in Table 24. Four fermentation runs were made
in which lla-hydroxycanrenone was produced by
bioconversion of canrenone. In two of these runs (R4A
and R4D), the bioconversion was conducted in
substantially the same manner as runs R3A and R3D of
Example 6. In run R4C, canrenone was converted to lla-
hydroxycanrenone generally in the manner described in
Example 3. In Run R4B, the process was carried out
generally as described in Example 4, i.e., with
sterilization of canrenone and growth medium in the
fermenter just prior to inoculation, all nitrogen and
phosphorus nutrients were introduced at the start of the
batch, and a supplemental solution containing glucose
only was fed into the fermenter to maintain the glucose
level as the batch proceeded. In the latter process (run
R4B), glucose concentration was monitored every 6 hours
and glucose solution added as indicated to control
glucose levels in the 0.5 to 1% range. The canrenone
addition schedules for these runs are set forth in
Table 25.
CA 02550897 1997-12-11
194
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CA 02550897 1997-12-11
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CA 02550897 1997-12-11
196
All fermenters were run under high agitation and aeration
during most of the fermentation cycle because the
fermentation beer had become highly viscous within a day
or so after inoculation.
Example 9
The transformation growth media, canrenone
addition schedules, harvest times, and degrees of
conversion for the runs of this Example are set forth in
Table 26.
Four bioconversion runs were carried out
substantially in the manner described for run R4B of
Example 8, except as described below. In run RSB, the
top turbine disk impeller used for agitation in the other
runs was replaced with a downward pumping marine
impeller. The downvuard pumping action axially poured the
broth into the center of the fermenter and reduced cake
formation. Methanol (200 ml) was added immediately after
inoculation in run RSD. Since canrenone was sterilized
in the fermenter, all nutrients except glucose were added
at the start of the batch, obviating the need for chain
feeding of sources of nitrogen, sources of phosphorus or
antibiotics.
CA 02550897 1997-12-11
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CA 02550897 1997-12-11
198
In order to-maintain immersion of the solid phase growing
above the liquid surface, growth medium (2 L) was added
to each fermenter 96 hours after the beginning of the
batch. Mixing problems were not entirely overcome by
either addition of growth medium or use of a downward
pumping impeller (run RSB) but the results of the runs
demonstrated the feasibility and advantages of the
process, and indicated that satisfactory mixing could be
provided according to conventional practices.
Example 10
Three bioconversion runs were carried out
substantially in the manner described in Example 9. The
transformation growth media, canrenone addition
schedules, harvest times, and degrees of conversion for
the runs of this Example are set forth in Table 27:
CA 02550897 1997-12-11
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CA 02550897 1997-12-11
200
Growth medium (1.3 L) and sterile water (0.8 L) were
added after 71 hours in run R6A to submerge mycelial cake
which had grown above the surface of the liquid broth.
For the same purpose, growth medium (0.5 L) and sterile
water (0.5 L) were added after 95 hours in run R68.
Material balance data showed that a better mass balance
could be determined where cake buildup above the liquid
surface was minimized.
Example 11
Fermentation runs were made to compare pre-
sterilization of canrenone with sterilization of
canrenone and growth medium in the transformation
fermenter. In run R7A, the process was carried out as
illustrated in Fig. 2, under conditions comparable to
those of runs R2C, R2D, R3A, R3B, R3D, R4A, and R4D. Run
R7H was as illustrated in Fig. 3 under conditions
comparable to those of Examples 4, 9 and l0; and run R4B.
The transformation growth media, canrenone addition
schedules, harvest times, and degrees of conversion for
the runs of this Example are set forth in Table 28:
CA 02550897 1997-12-11
201
TABLE 28 - Process
Description of
the
Experiment of l0
L Scale Bioconversions
Run Number R7A R7B
Medium (g/L)
corn steep liq. 30 the same as run
Yeast extract 15 R7A
NH,H2 P0, 3
Glucose 15
OSA 0.5 ml
pH adjusted to 6.5
with 2.5NNaOH
Canrenone charge 160 g canrenone 160 g canrenone
was sterilized was sterilized
&
blended outside in the fermenter
the fermenter
Medium charge Glucose feeding; Glucose feeding;
canrenone was no other
added with 1.6L addition
growth medium
Harvest time 118.5 hrs. 118.5 hrs.
Bioconversion 93% 89%
A mass balance based on the final sample taken from run
R7B was 89.5%, indicating that no significant substrate
loss or degradation in bioconversion. Mixing was
determined to be adequate for both runs.
Residual glucose concentration was above the
desired 5-l0 g per liter control range during the initial
80 hours. Run performance was apparently unaffected by a
light cake that accumulated in the head space of both the
fermenters.
Example 12
Extraction efficiency was determined in a
series of 1 L extraction runs as summarized in Table 29.
In each of these runs, steroids were extracted from the
mycelium using ethyl acetate (1 L/L fermentation volume).
Two sequential extractions were performed in each run.
Based on RP-HPLC, About 80% of the total steroid was
CA 02550897 1997-12-11
202
recovered in the first extraction; and recovery was
increased to 95% by the second extraction. A third
extraction would have recovered another 3% of steroid.
The remaining 2% is lost in the supernatant aqueous
phase. The extract was drawn to dryness using vacuum but
was not washed with any additional solvent. Chasing with
solvent would improve recovery from the initial
extraction if justified by process economics.
TABLE 29 - Recovery-of
lla-Hydroxycanrenone
at 1 Liter Extraction
(% of Total)
Run Number 1st 2nd 3rd Supernatant
Extract Extract Extract
R5A 79% 16% 2% 2%
R5A 84% 12% 2% 2%
R4A 72% 20% 4% 4%
R4A 79% 14% 2% 5%
R4B 76% 19% 4% 1%
R4H 79% 16% 3% 2%
R4B 82% 15% 2% 1%
Average 79% 16% 3% 2%-
Methyl isobutyl ketone (MINK) and toluene were evaluated
as extraction/crystallization solvents for lla-
hydroxycanrenone a~ the 1 L broth scale. Using the
extraction protocol as described hereinabove, both MIBK
and toluene were comparable to ethyl acetate in both
extraction efficiency and crystallization performance.
Example 13
As part of the evaluation of the processes of
Figs. 2 and 3, particle size studies were conducted on
the canrenone substrate provided at the start of the
fermentation cycle in each of these processes. As
described above, canrenone fed to the process of Fig. 1
CA 02550897 1997-12-11
203
was micronized before introduction into the fermenter.
In this process, the canrenone is not sterilized, growth
of unwanted microorganisms being controlled by addition
of antibiotics. The processes of Figs. 2 and 3 sterilize
the canrenone before the reaction. In the process of
Fig. 2, this is accomplished in a blender before
introduction of canrenone into the fermenter. In the
process of Fig. 3, a suspension of canrenone in growth
medium is sterilized in the fermenter at the start of the
batch. As discussed hereinabove, sterilization tends to
cause agglomeration of canrenone particles. Because of
the limited solubility of canrenone in the aqueous growth
medium, the productivity of the process depends on mass
transfer from the solid phase, and thus may be expected
to depend on the interfacial area presented by the solid
particulate substrate which in turn depends on the
particle size distribution. These considerations
initially served as deterrents to the processes of Figs.
2 and 3.
However, agitation in the blender of Fig. 2 and
the fermentation tank of Fig. 3, together with .the action
of the shear pump used for transfer of the batch in Fig.
2, were found to degrade the agglomerates to a particle
size range reasonably approximate that of the
unsterilized and micronized canrenone fed to the process
of Fig. 1. This is illustrated by the particle size
distributions for the canrenone as available at the
outset of the reaction cycle in each of the three
processes. See Table 30 and Figs. 4 and 5.
TABLE 30
- Particle
Distributions
of
Three Different
Canrenone
Samples
Sample 45- <180 mean Run #: %
125 ~ ~, size Bioconversion
CA 02550897 1997-12-11
204
Canrenone 75% 95% -- R3C:
shipment . 93.1% (120 h)
R4 C
96.3% (120 h)
Blended 31.2% 77.2 139.5 R3A:
Sample % 94.6% (120 h)
R3B:
95.2% (12 0 h)
Sterilize 24.7% 65.1 157.4 R4B:
d Sample % 97.6% (120 h)
RSB:
93.8% (120 h)
From the data in Table 30, it will be noted that
agitators and shear pump were effective to reduce the
average particle size of the sterilized canrenone to the
same order of magnitude as the unsterilized substrate,
but a significance size difference remained in favor of
the unsterilized substrate. Despite this difference,
reaction performance data showed that the pre-
sterilization processes were at least as productive as
the process of Fig. 1. Further advantages may be
realized in the process of Fig. 2 by certain steps for
further reducing and controlling particle size, e.g., wet
milling of sterilized canrenone, and/or by pasteurizing
rather than sterilizing.
2 0 Exactro 1 a 14
A seed culture was prepared in the manner
described in Example 5. At 20 hours, the mycelia in the
inoculum fermenter was pulpy with a 40% PMV. Its pH was
5.4 and 14.8 gp1 glucose remained unused.
A transformation growth medium (35 L) was
prepared having the composition shown in Table 20. In
the preparation of feeding medium, glucose and yeast
extract were sterilized separately and mixed as a single
feed at an initial concentration of 30% by weight glucose
CA 02550897 1997-12-11
205
and 10% by weight yeast extract, pH of the feed was
adjusted to 5.7.
Using this medium, tTable 20), two
bioconversion runs were made for the conversion of
canrenone to llcx-hydroxycanrenone. Each of the runs was
conducted in a 60 L fermenter provided with an agitator
comprising one Rushton turbine impeller and two Lightnin'
A315 impellers.
Initial charge of the growth medium to the
fermenter was 35 L. Micronized and unsterilized
canrenone was added to an initial concentration of 0.5%:
The medium in the fermenter was inoculated with a seed
culture prepared in the manner described in Example 5 at
an initial inoculation ratio of 2.5%. Fermentation was
carried out at a temperature of 28°C, an agitation rate
of 200 to 500 rpm, an aeration rate of 0.5 vvm, and
backpressure sufficient to maintain a dissolved oxygen
level of at least 20% by volume. The transformation
culture developed during the production run was in the
form of very small oval pellets (about 1-2 mm).
Canrenone and supplemental nutrients were chain f.ed to
the fermenter generally in the manner described in
Example 1. Nutrient additions were made every four hours
at a ratio of 3.4 g glucose and 0.6 g yeast extract per
liter of broth in the fermenter.
set forth in Table 31 are the aeration rate,
agitation rate, dissolved oxygen, PMV, and pH prevailing
at stated intervals during each of the runs of this
Example, as well as the glucose additions made during the
batch. Table 32 shows the canrenone conversion profile.
Run R11A was terminated after 46 hours; Run R11B
continued for 96 hours. In the latter run; 93%
conversion was reached at 81 hours; one more feed
addition was made at 84 hours; and feeding then
terminated. Note that a significant change in viscosity
CA 02550897 1997-12-11
206
occurred between the time feeding was stopped and the end
of the run.
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CA 02550897 1997-12-11
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CA 02550897 1997-12-11
211
Example 15
Various cultures were tested for effectiveness
in the bioconversion of canrenone to licx-hydroxycanrenone
according to the methods generally described above.
A working cell bank of each of Ast~erc~~illus
pi er ATCC 11394, Rhizo~us arrhizus ATCC 11145 and
Rhizor~us stolonifer ATCC 6227b was prepared in the manner
described in Example 5: Growth medium (50 ml) having the
composition set forth in Table 18 was inoculated with a
to suspension of spores (1 ml) from the working cell bank
and placed in an incubator. A seed culture was prepared
in the incubator by fermentation at 26°C for about 20
hours. The incubator was agitated at a rate of 200 rpm.
Aliquots (2 m1) of the seed culture of each
microorganism were used to inoculate transformation
flasks containing the growth medium (30 ml) of Table l8.
Each culture was used for inoculation of two flasks, a
total of six. Canrenone (200 mg) was dissolved in
methanol (4 ml) at 36°C, and a 0.5 ml aliquot of this
solution was introduced into each of the flasks.
Bioconversion was carried out generally under the
conditions described in Example 5 with additions of 50%
by weight glucose solution (1 ml) each day. After the
first 72 hours the following observations were made on
the development of mycelia in the respective
transformation fermentation flasks:
ATCC 11394 - good even growth
ATCC 11145 - good growth in first 48 hours, but mycelial
clumped into a ball; no apparent growth in last 24 hours;
ATCC 6227b - good growth; mycelial mass forming clumped
ball.
CA 02550897 1997-12-11
212
Samples of the broth were taken to analyze for the extent
of bioconversion. After three days, the fermentation
using ATCC 11394 provided conversion to lla-
hydroxycanrenone of 80 to 90%; ATCC 11145 provided a
conversion of 50%; and ATCC 6227b provided a conversion
of 80 to 90%.
Example 16
Using the substantially the method described in
Example 15, the additional microorganisms were tested for
effectiveness in the conversion of canrenone to lla
hydroxycanrenone. The organisms tested and the results
of the tests are set forth in Table 33:
CA 02550897 1997-12-11
213
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CA 02550897 1997-12-11
214
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CA 02550897 1997-12-11
215
Example l7
Various microorganisms were tested for
effectiveness in the conversion of canrenone to 9a-
hydroxycanrenone. Fermentation media for the rune of this
Example were prepared as set forth in Table 34:
TABLE 34
Soybean Meal:
dextrose 20 g
soybean meal 5 g
NaCl 5 g
yeast extract 5 g
KH2 P04 5 g
water to l L
pH 7.0
Peptone/yeast extract/glucose:
glucose 40 g
bactopeptone 10 g
yeast extract 5g
water to 1 L
Mueller-Hinton:
beef infusion 300 g
casamino acids 17.5 g
starch 1.5 g
water to 1 L
Fungi were grown in soybean meal medium and in peptone-
yeast extract glucose; atinomycetes and eubacteria were
grown in soybean meal (plus 0.9~ by weight Na formate for
biotransformations) and in Mueller-Hinton broth.
Starter cultures were inoculated with frozen
spore stocks (20 ml soybean meal in 250 ml Erlenmeyer
flask). The flasks were covered with a milk filter and
bioshield. Starter cultures (24 or.48 hours old) were
used to inoculate metabolism cultures (also 20 ml in 250
ml Erlenmeyer flask) - with a 10% to 15% crossing volume -
and the latter incubated for 24 to 48 hours before
CA 02550897 1997-12-11
216
addition of steroid substrate far the transformation
reaction.
Canrenone was dissolved/suspended in methanol
(20 mg/ml), filter sterilized, and added to the cultures
to a final concentration of O.l mg/ml. All
transformation fermentation flasks were shaken at 250 rpm
(2" throw) in a controlled temperature room at 26°C and
60% humidity.
Biotransformations were harvested at 5 and 48
hours; or ~t 24 hours, after addition of substrate.
Harvesting began with the addition of ethyl acetate (23
ml) or methylene chloride to the fermentation flask. The
flasks were then shaken for two minutes and the contents
of each flask poured into a 50 ml conical tube: To
separate the phases, tubes were centrifuged at 4000 rpm
for 20 minutes in a room temperature unit: The organic
layer from each tube was transferred to a 20 ml
borosilicate glass vial and evaporated in a speed vac.
Vials were capped and stored at -20°C.
To obtain material for structure determination,
biotransformations were scaled up to 500 ml by increasing
the number of shake flask fermentations to 25. At the
time of harvest (24 or 48 hours after addition of
substrate), ethyl acetate was added to each flask
individually, and the flasks were capped and put back on
the shaker for 20 minutes. The contents of the flasks
were then poured into polypropylene bottles and
centrifuged to separate the phases, or into a separatory
funnel in which phases were allowed to separate by
gravity. The organic phase was dried, yielding crude
extract of steroids contained in the reaction mixture.
Reaction product was analyzed first by thin
layer chromatography on silica gel (250 Vim) fluorescence
backed plates (254 nm) . Ethyl acetate (500 JCL was added
to each vial containing dried ethyl acetate extract from
the reaction mixture.Further analyses were conducted by
i
CA 02550897 1997-12-11
217
high performance liquid chromatography and mass
spectrometry. TLC plates were developed in a 95:5 v/v
chloroform/methanol solvent mixture.
Further analysis was conducted by high
performance liquid chromatography and mass spectrometry.
A waters HPLC with Millennium software, photodiode array
detector and autosampler was used. Reversed phase HPLC
used a waters NovaPakl''' C-18 (4 ~cm particle size) RadialPak~"'
4 mm cartridge. The 25 minute linear solvent gradient
began with the column initialized in water:acetonitrile
(75:25), and ended at water:acetonitrile (25:75). This
was followed by a three minute gradient to 100%
acetonitrile and 4 minutes of isocratic wash before
column regeneration in initial conditions.
For LC/MS, ammonium acetate was added to both
the acetonitrile and water phases at a concentration of 2
nM. Chromatography was not significantly affected.
Eluant from the column was split 22:1, with the majority
of the material directed to the PDA detector. The
remaining 4.5% of the material.was directed to the
electrospray ionizing chamber of an Sciex'''°'API III mass
spectrometer. Mass spectrometry was accomplished in
positive mode. An analog data line from the PDA detector
on the HPLC transferred a single wave length chromatogram
to the mass spectrometer for coanalysis of the UV and~MS
data.
Mass spectrometric fragmentation patterns
proved useful in sorting from among the hydroxylated
substrates. The two expected hydroxylated canrenones,
lla-hydroxy- and 9a-hydroxy,~ lost water at different
frequencies in a consistent manner which could be used as
a diagnostic. Also, the 9a-hydroxycanrenone formed an
ammonium adduct more readily than did lla-
hydroxycanrenone. Set forth in Table 35 is a summary of
the TLC, HPLC/UV and LC/MS data for canrenone
fermentations, showing which of the tested microorganism
CA 02550897 1997-12-11
218
were effective in the bioconversion of canrenone to 9a-
hydroxycanrenone. Of these, the preferred microorganism
was Corynes~ora cassiicola ATCC 16718.
CA 02550897 1997-12-11
219
TABLE 35 - Summary of TLC,
HPLC/W, and LC/MS
Data for Canrenone Fermentations
Evidence
for 9aOH-canrenone
Culture TLC spot HPLC-peak MS: 357
at 9aQH- at 9aOH- (M + H),
AD canrenone 3 3 9 (
-Hz0)
w/W & 375
(+~4)
Absidia coerula ATCC n y y/n
6647
Absidia alauca ATCC n
22752
Actinomucor eleaans ATCC tr y tr
6476
Asperaillus flavi~es tr
ATCC 1030
Asneraillus fumiqatus tr y n
ATCC 26934
As~eraillus nidulans tr y y
ATCC 11267
Asperaillus nicer ATCC n y y
16888
Asperaillus nicer ATCC n y n
26693
Asperaillus ochraceus n y n
ATCC 18500
Bacterium clrclo-oxvdans n tr n
(Searle) ATCC 12673
Heauveria bassiana ATCC tr y y
7159
Beauveria bassiana ATCC y y y
13144
Botryosphaeria obtusa y tr tr
IMI 038560
Calonectria decora ATCC n tr y
14767
Chaetomium cochliodes tr tr y/n
ATCC 10195
Comomonas testosterone tr tr n
(Searle) ATCC 11996
Corvnespora cassiicola y y y
ATCC 16718
CA 02550897 1997-12-11
220
~unninahamella y y y
blakesleana ATCC 8688a
Cunninahamella y y y
echinulata ATCC 3655
~unninahamella elecrans y y y
ATCC 9245
Curcularia clavata ATCC n y y/n
22921
Curvularia lunata ATCC y n n
12071
Cvl indrocart~on tr n n
radicicola (Searle) ATCC
11011
~~icoccum humucola ATCC y y y
12722
E.picoccum orvzae ATCC tr tr tr
12724
Fusarium oxvs~orum ATCC tr
7601
Fusarium oxvsporum f.sp. n
ce~ae ATCC 11171
Gibberella fuiikuroi tr y y
ATCC 14842
Gliocladium deliauescens y tr tr
ATCC 10097
Gonaronella butieri ATCC y y W? y
22822
Hvnom~ces chrysosbermus y y y
Tul. IMI 109891
Linomyces liuofer ATCC n
10792
Melanospora ornata ATCC tr n n
26180
Mortierella isabellinav y y n
ATCC 42613
Mucor grisco-cyanus ATCC n
1207a
Mucor mucedo ATCC 4605 tr
Mycobacterium fortuitumn
NRRL H8119
Myrothecium verrucaria tr tr y
ATCC 9095
CA 02550897 1997-12-11
221
Nocardia aurentia n tr n
(Searle) ATCC 12674
Nocardia cancicruria y y n
ATCC 31548
Nocardia corallina ATCC n
19070
Paecilomvces carneus n y n
ATCC 46579
Penicillium chrvsoQenum n
ATCC 9480
Penicillium r~atulum ATCC y y y/n
24550
Penicillium ournuro9~enum tr y y
ATCC 46581
Pithomyces atro- tr y tr
olivaceus ATCC 6651
Pithomvces cvnodpntis n tr tr
ATCC 26150
Phvcomvces blakesleeanus y y y/n
IMI 118496
Pvcnosnorium sp. ATCC y y y/n
12231
Rhizo~oQOn sp. ATCC
36060
Rhizopus arrhizus ATCC tr y n
11145
RhizoDUS stolonifer ATCC n
6227b
Rhodococcus eaui ATCC n tr n
14887
Rhodococcus eaui ATCC tr tr n
21329
Rhodococcus sue. ATCC n n n
19070
Rhodococcus rhodochrous n tr n
ATCC 19150
Saccharopolvspora y y y
a thaea ATCC 11635
Sepedonium ampullosporum n n n
IMI 203033
Sepedonium chrvsospermum n
ATCC 13378
CA 02550897 1997-12-11
222
Septomvxa affinis ATCC n y W? y/n
6737
Stachvlidium bicolor y y y/n
ATCC 12672
Streptomyces n
californicus ATCC 15436
Streptomvces n
cinereocrocatus ATCC
3443
Stre~tomvces coelicolor n
ATCC 10147
Streptomvces flocculus
ATCC 25453
Streptomyces fradiae n
ATCC 10745
Streptomvces griseus n
subsp. griseus ATCC
13968
Streptomvces griseus n
ATCC 11984
Streptomyces hydroQenans n
ATCC 19631
Streptomyces y y y
h roscotiicus ATCC 27438
Stre~tomyces lavendulae n
Panlab 105
Streptomvces n
paucisporogenes ATCC
25489
StreDtomvces n tr tr
Dur urascens ATCC 25489
Streotomyces
roseochromogenes ATCC
13400
Streptomyces spectabilis n
ATCC 27465
Stysanus microsporus
ATCC 2833
Svnce~halastrum n
racemosum ATCC 18192
Thamnidium elecrans ATCC
18191
Thamnostylum piriforme y tr
ATCC 8992 y
CA 02550897 1997-12-11
223
Thielavia terricolan n
ATCC 13807
Trichoderma viride ATCC n
26802
Trichothecium roseum tr y y/n
ATCC 12543
Verticillium theobromae y tr tr
ATCC 12474
Example 18
Various cultures were tested for effectiveness
in the bioconversion of androstendione to lla-
hydroxyandrostendione according to the methods generally
described above.
A working cell bank of each of AsDercTillus
ochraceus NRRL 405 (ATCC 18500); Asoergillus niqer ATCC
11394; Asneraillus nidulans ATCC 11267; Rhizogus orvzae
ATCC 11145; Rhizopus stolonifer ATCC 6227b; Trichothecium
roseum ATCC 12519 and ATCC 8685 was prepared essentially
in the manner described in Example 4. Growth medium (50
ml) having,the composition set forth in Table 18 was
inoculated with a suspension of spores (1 ml) from the
working cell bank and placed in an incubator. A seed
culture was prepared in the incubator by fermentation at
26°C for about 20 hours. The incubator was agitated at a
rate of 200 rpm.
Aliquots (2 ml) of the seed culture of each
microorganism were used to inoculate transformation
flasks containing the growth medium (30 ml) of Table 15.
Each culture was used for inoculation of two flasks, a
total of 16. Androstendione (300 mg) was dissolved in
methanol (6 ml) at 36°C, and a 0.5 ml aliquot of this
solution was introduced into each of the flasks.
Bioconversion was carried out generally under the
conditions described in Example 6 for 48 hours. After 48
hours samples of the broth were pooled and extracted with
ethyl acetate as in Example 17. The ethyl acetate was
CA 02550897 1997-12-11
224
concentrated by evaporation, and samples were analyzed by
thin layer chromatography to determine whether a product
having a chromatographic mobility similar to that of lla-
hydroxy-androstendione standard (Sigma Chemical Co.; St.
Louis) was present. The results are shown in Table 36.
Positive results are indicated as "+".
TABLE 36
Bioconversion of androstendione
to 11 alpha-
hydroxy-androstendione
Culture ATTC# media TLC
results
Rhizopus oryzae 11145 CSL +
Rhizopus stolonifer 6227b CSL +
Aspergillus nidulans 11267 CSL +
Aspergillus niger 11394 CSL +
Aspergillus ochraceus NRRL 405 CSL +
Aspergillus ochraceus 18500 CSL +
Trichothecium roseum 12519 CSL +
Trichothecium roseum 8685 CSL +
The data in Table 36 demonstrate that each of
listed cultures was capable of producing a compound from
androstendione having the same i~.f value as that of the
lla-hydroxyandrostendione standard.
Asperaillus ochraceus NR.RL 405 (ATCC 18500) was
retested by the same procedure described above, and the
culture products were isolated and purified by normal
phase silica gel column chromatography using methanol as
the solvent. Fractions were analyzed by thin layer
chromatography. TLC plates were Whatman K6F silica gel
r
CA 02550897 1997-12-11
225
60~, 10x20 size, 250, thickness. The solvent mixture was
chloroform: methanol, 95:5, v/v. The crystallized product
and lla-hydroxyandrostendione standard were both analyzed
by LC=MS and NNIR spectroscopy. Both compounds yielded
similar profiles and molecular weights.
Example 19A
Various microorganisms were tested for
effectiveness in the bioconversion of androstendione to
ll~i-hydroxyandrostendione essentially by the methods
described above in Examples 17 and 18.
Cultures of each of As~ergillus fumiaatus ATCC
26934, As~eraillus ni er ATCC 16888 and ATCC 26693,
Epicoccum oryzae ATCC 7156, Curvularia lunata ATCC 12017,
Cunninahamei.la blakesleeana ATCC 8688a, and Pithomvces
atro-olivaceus IFO 6651 were grown essentially in the
manner described in Example 17. Growth and fermentation
media (30 ml) had the composition shown in Table 34.
The ll~i-hydroxylation of androstendione by the
above-listed microorganisms was analyzed using
essentially the same methods of product identification
described in Examples 17 and 18. The results are set
forth in Table 19A-1.
Table 19A-1
11a-Hydroxylation of Androstendione
by Various Microorganisms
Organism TLC LC MS
Asr~ercrillus fumiaatus + +
ATCC 26934
Asperaillus niQer + +
ATCC 16888
and ATCC 26693
Epicoccum oryzae + +
CA 02550897 1997-12-11
226
ATCC 7156
Curvularia lunata + +
ATCC 12017
Cunninahamella blakesleeana + +
ATCC 8688a
Pithomvces atro-olivaceus
IFO 6651 + +
In Table 19A-1, a "+" indicates a positive
result, i.e., an Rf as expected in thin layer
chromatography and an approximately correct molecular
weight upon LC/MS.
These results demonstrate that the listed
micro-organisms are capable of carrying out the 11~3-
hydroxylation of androstendione.
Example 19B
Various microorganisms were tested for effectiveness
in the conversion of mexrenone to ll~i-hydroxymexrenone.
Fermentation media for this example were prepared as
described in Table 34.
The fermentation conditions and analytical methods
were the same as those in Example 17. TLC plates and the
solvent system were as described in Example 18. The
rationale for chromatographic analysis is as follows:
11a-hydroxymexrenone and llcx-hydroxycanrenone have the
same chromatographic mobility. lla-hydroxycanrenone and
9a-hydroxycanrenone exhibit the same mobility pattern as
lla-hydroxyandrostendione and 11a-hydroxyandrostendione.
Therefore, 11Q-hydroxymexrenone should have the same
mobility as 9a-hydroxycanrenone. Therefore, compounds
extracted from the growth media were run against 9a-
hydroxycanrenone as a standard. The results are shown in
Tabla 36.
CA 02550897 1997-12-11
227
TABLE 37
Summary of TLC Data for
11(3-hydroxymexren one Formation
from Mexr enone
Spot
Microorganism Medium' Character'
Absidia coerula ATCC 6647 M,S strong
Asperaillus niQer ATCC S,P faint (S)
16888 ~ (P)
Heauveria bassiana ATCC P strong
7159
Beauveria bassiana ATCC S,P ?,?
13144
Hotryosphaeria obtusa IMI faint
038560
Cunninahamella
blakesleeana ATCC 8688a S,P strong
echinulata ATCC 3655 S,P strong
eleaans ATCC 9245 S,P strong
Curvularia lunata ATCC S strong
12017
Gongronel.la butleri ATCC S,P strong
22822
Penicillium Datulum ATCC S,P strong
24550
Penicillium ~urpuroaenum S,P strong
ATCC 46581
Pithomyces atro-olivaceus S,P faint
IFO 6651
Rhodococcus eQUi ATCC M faint
14887
Saccharo~olvspora erythaea M, SF faint
ATCC 11635
Streotom~rces hygroscopicus M, SF strong
ATCC 27438
Streptom~ces purnurascens M,SF ~ faint
ATCC 25489
Thamnidium eleQans ATCC S,P faint
18191
CA 02550897 1997-12-11
228
Thamnostvlum piriforme S,P faint
ATCC 8992
Trichothecium roseum ATCC P, S faint (P)
12543 ? (S)
' M = Mueller-Hinton
P = PYG (peptone/yeast extract/glucose)
S = soybean meal
SF = soybean meal plus formate
' ? - questionable difference from no substrate control
These data suggest that the majority of the
organisms listed in this table produce a product similar
or identical to 11Q-hydroxymexrenone from mexrenone.
Example 19C
Various microorganisms were tested for effectiveness
in the conversion of mexrenone to lla-hydroxymexrenone,
o1~2-mexrenone, 6~i-hydroxymexrenone, 12(3-hydroxymexrenone,
and 9a-hydroxymexrenone. Mexrenone can be prepared in
the manner set forth in Weier, U.S. Patent No. 3,787,396
and R.M. Weier et al., J:Med.Chem., Vol. 18, pp. 817-821
(1975). Fermentation~media were prepared as described in example
17, except that mexrenone was included. The fermentation
conditions were essentially the same as those in Example
17; analytical methods were also the same as those in
Examples 17 and 18. TLC plates and the solvent system
were as described in Examples 17 and 18.
The microorganisms tested and results obtained
therewith are shown in Table 19C-1.
CA 02550897 1997-12-11
229 .
Table 19C-1
Production of llcx-hydroxymexrenone from
Mexrenone
by Various Microorganisms
Organism 'PLC HPLC m z
47:399
Heauveria bassiana + + 5:1
ATCC 7159
Heauveria bassiana + + 10: 1
ATCC 13144
Mortierella isabella + + 1:1
ATCC 42613
_Cunninahamella blakesleeana + + 1:1
ATCC 8688a
Cunninahamella echinulata + + 1:2
ATCC 3655
Cunninghamella eleaans + + 1:1
ATCC 9245
Absidia coeruha + + 1:1
ATCC 6647
As~eraillus ni er + + 4:1
ATCC 16888
Gonqronella butieri + + 3:1
ATCC 22822
Pithomyc.es atro-olivaceus + . + 3:1
ATCC 6651
Streptomyces hvaroscopicus + + 3:1
ATCC 27438
In Table 19C-1, a +~~ indicat es a positive
result, i.e., an Rt as expected in thin layer
chromatography and a retention time as expected in HPLC.
m/z 417:399 indicates the peak height atio of he 417
r t
molecule thydroxymexrenone~ and the 399 molecule
CA 02550897 1997-12-11
230
(mexrenone). The standard has a 10:1 ratio of peak
height for m/z 417 to m/z 399.
The product obtained from Beauveria bassiana
ATCC 13144 was isolated from the incubation mixture and
analyzed by NMR, and the structural profile thereby
confirmed to be 11a-hydroxymexrenone. By analogy, the
products obtained from the other microorganisms listed in
Table 19C-1 were also presumed to be lla-
hydroxymexrenone.
Table 19C-2
Production of ale-Mexrenone from Mexrenone
by Various Microoraanims
Organism m z 399 HPLC TLC
Rhodococcus a ui
ATCC 148875 + + +
Bacterium cvclo-oxvdans
ATCC 12673 + + +
Comomonas testosterone + + +
ATCC 11996
Nocardia aurentia + + +
ATCC 12674
Rhodococcus equi + + +
ATCC 21329
In Table 19C-2, a "+" indicates a positive
result, e.9., an Rf as expected in thin layer
chromatography, a retention time as expected in HPLC,
etc.
The product obtained from Bacterium.cvclo-
oxydans ATCC 12673 was isolated from the incubation
mixture and analyzed by NMR, and the structural profile
thereby confirmed to be o1~2-mexrenone. By analogy, the
products obtained from the other microorganisms listed in
Table 19C-2 were also presumed to be n1~2-mexrenone.
CA 02550897 1997-12-11
231
Production of 6(i- and 12li-h,3rdroxvmexrenone
Mortierella isabella ATCC 42613 was grown as in
Example 17 in the presence of mexrenone. The
fermentation products were isolated and purified by flash
chromatography. The purified products were analyzed by
LC/MS as in Examples 17 and 18, and proton NMR and
carbon-13 NMR. The data indicated that the products
included 6Q- and 12~i-hydroxymexrenone.
Table 19C-3
Production of 9a-Hydroxymexrenone from
Mexrenone by Various Microorganisms
Organism m z 417 HPLC TLC
Streptomyces hygrosconicus
ATCC 27438 + + +
Goncrronella butleri
ATCC 22822 + + +
Cun~n',nahamella blakesleeana
ATCC 8 8~; , ' + + +
Cunnina amella echo-riulata
ATCC 3655 + + +
Cunninahamella elecrans
ATCC 9245 + + +
Mortierella isabellina
ATCC 42613 + + +
Absidia coerula
ATCC 6647 + + +
Beauveria bassiana
ATCC 7159 + + +
Beauveria bassiana
ATCC 13144 + + +
AsperQillus niger
CA 02550897 1997-12-11
232
ATCC 16888 + + +
The microorganisms listed in Table 19C-3 were
grown under the same conditions as in Example 17, in the
presence of mexrenone. The fermentation products were
analyzed by TLC and LC/MS as in Examples l7 and 18. A
°+° indicates a positive result, e.g., an Rf as. expected
in thin-layer chromatography, a retention time as
expected in HPLC, etc. The data suggest that the
products include 9a-hydroxymexrenone.
Example 19D
Various microorganisms were tested for
effectiveness in the conversion of canrenone to e9.m-
canrenone. The fermentation media and growth conditions
were essentially the same as in Example 17, except that
canrenone was included in the medium. The analytical
methods were as described in Examples I7 and 18. The
microorganisms and results are shown in Table 19D-1,
below.
Table 19D-1
Production of ~9~11-Canrenone from Canrenone
by Various Microorganisms
Organism m z 339 HPLC TLC
Bacterium cyclo-oxvdans
ATCC 12673 + + +
Comomonas testosteroni
ATCC 11996 + + +
Cylindrocarpon radicicola
ATCC 11011 + + +
Paecilomyces carneus
CA 02550897 1997-12-11
233
ATCC 46579 + + +
Septomvxa affinis
ATCC 6737 + + +
Rhodococcus spp.
ATCC 19070 + + +
The fermentation products were analyzed by TLC
and LC/MS as in Examples 17 and 18. A "+" indicates a
positive result, e.g., an Rf as expected in thin layer
chromatography, a retention time as expected in HPLC,
etc.
The product obtained from Comomonas
testosterone ATCC 11996 was isolated from the growth
medium and analyzed by W spectroscopy. The
spectroscopic profile' confirmed the presence of p9.11-
canrenone. By analogy, the products obtained from the
other microorganisms listed in Table 19D-1 were also
presumed to be 09'11-canrenone.
Example 20A
Scheme 1: Step 1: Method A: Preparation of
5'R(5'a),7'(3-20'-Aminohexadecahydro-11'~i-hydroxy-
10'a,13'a-dimethyl-3',5-dioxospiro[furan-2(3H),17'a(5'H)-
[7, 4] metheno [4H [cyclopenta [a] phenanthrene] -5' -
carbonitrile.
Into a 50 gallon glass-line reactor was charged
61.2 L (57.8 kg) of DMF followed by 23.5 Kg of 11-
hydroxycanrenone 1 with stirring. To the mixture was
added 7.1 kg of lithium chloride. The mixture was
stirred for 20 minutes and 16.9 kg of acetone cyanohydrin
was charged followed by 5.1 kg of triethylamine. The
mixture was heated to 85°C and maintained at this
temperature for 13-18 hours. After the reaction 353 L of
water was added followed by 5.6 kg of sodium bicarbonate.
The mixture was cooled to 0°C, transferred to a 200
CA 02550897 1997-12-11
234
gallon glass-lined reactor and quenched with 130 kg of
6.7% sodium hypochlorite solution slowly. The product
was filtered and washed with 3 x 40 L-portions of water
to give 21.4 kg of the product enamine.
0 0
,,
LICI, DMF. EI~N,
Acetone cyanohyd~in
85°C. 8-15 h
O
Step 1
NHp
Hl NMR (DMSO-d6) : 7.6 (2H, bd) , 4.53 (1H, d, .
J=5.9) , 3.71 (1H, m) , 3 . 0-1.3 (17H, m) , 1.20 (5H, m) ,
0.86 (3H,s) , 0.51 (lH,t, J=10) .
Example 20B
l0 Preparation of 7a-cyano-l1a,17-dihydroxy-3-oxo-17a-pregn-
4-ene-21-carboxylic acid, ~-lactone
0
H o,,, o .
i
o ~~'~cN
CA 02550897 1997-12-11
235
50.0g of 11-hydroxycanrenone and 150.0 mL of
dimethylacetamide were added to a clean, dry three-necked
flask equipped with a mechanical stirrer, condenser,
thermocouple and heating mantle. 16.0 mL of a sulfuric
acid solution (prepared by mixing 50.0 mL of sulfuric
acid (98.?% Baker grade) with 50.0 mL of water) was added
to this mixture. A sodium cyanide solution comprising
15.6g of sodium cyanide and 27.0 mL of water was then
added.
The resulting mixture was heated at 80°C for 7
hours, the degree of conversion being periodically
checked by TLC or HPLC. After approximately ? hours,
HPLC of the mixture indicated the presence of the ?-cyano
compound. The mixture was then stirred overnight and
allowed to cool to room temperature (about 22°C). 200 mL
of water was added to the mixture followed by 200 mL of
methylene chloride and the resulting two phase mixture
stirred and the phases were then allowed to separate.
The aqueous layer was a gel. 100 mL of sodium
bicarbonate solution was added to the aqueous layer in an
unsuccessful attempt to break up the gel. The aqueous
layer was then discarded.
The separated methylene chloride layer was
washed with 100 mL of water and the resulting two phase
mixture stirred. The phases were then allowed to
separate and the separated methylene chloride layer Was
filtered through 200g of silica gel (Aldrich 200-400
mesh, 60A). The filtrate was concentrated to dryness
under reduced pressure at 45°C using a water aspirator to
provide about 53.9 g of a crude solid product. The crude
solid product then was dissolved in 50 mL of methylene
chloride and treated with 40 mL of 4N hydrochloric acid
in a separatory funnel and the two phase mixture allowed
to separate. The methylene chloride layer was washed
with 50 mL of water. The combined aqueous layers were
extracted with 50 mL of methylene chloride chloride. The
CA 02550897 1997-12-11
236
combined methylene chloride layers were then dried over
sodium sulfate to provide 45 g of a solid which was a
mixtuture of lla-hydroxycanrenone and the product, 7a-
cyano-l1a,17-dihydroxy-3-oxo-17a-pregn-4-ene-21-
carboxylic acid, 'y-lactone.
A sample of the product was analyzed by HPLC
(column: 25cm x 4.6mm, 5~ Altima C18LL); solvent gradient:
solvent A = water/trifluoroacetic acid= 99.9/0.1,
solvent H = acetonitrile/ trifluoroacetic acid =
99.9/0.1, flow rate = 1.00 mL/minute, gradient 65:30
(v/v) (A:H--initial), 35:65 (v/v) (A:H--after 20
minutes), 10:90 (v/v) (A:H--after 25 minutes); diode
. array detector) which revealed a ~",~ of 238 nm.
The reaction mixture was analyzed by HPLC-NMR
using the following conditions: HPLC--column: Zorba~'" RX-
C8 (25cm x 4.6mm, S~C) using a solvent gradient from 75%
D~0,25% acetonitrile to 25% D20, 75% acetonitrile over 25
minutes with a flow of 1 mL/minute; 1H NMR (obtained
using WET solvent suppression): 5.84 (s,lH), 4.01 (m,lH),
3.2 (m,lH), 2.9-1.4 (m, integral not meaningful due to
solvent suppression of acetonitrile), 0.93-0.86 (s,
overlapping 3H, and t,2H).
Example 20C
Preparation of 5Q,7a-dicyano-17-hydroxy-3-oxo-l7cr-
pregnane-21-carboxylic acid, y-lactone
0
0
..".l
0
CN
CA 02550897 1997-12-11
237
102 g (0.3 mol) of 17-hydroxy-3-oxo-17a-pregna-
4,6-diene-21-carboxylic acid, y-lactone (canrenone) was
slurried with 46.8 g (0.72 mol) of potassium cyanide,
78.6 mL (1.356 mols) of acetic acid, and 600 mL of
methanol in a three liter, three neck, round bottom
flask. 64.8 mL (0.78 mol) of pyrrolidine was added to
the mixture and the combined slurry heated to reflux
(64°C) and maintained for about 1.5 hours: The
temperature of the slurry was then lowered to 25°C to
30°C over a ten minute period with a cooling bath. 120
mL of a concentrated hydrochloric acid was slowly added
during the cooldown as a tan colored solid precipitated.
The mixture was stirred at 25°C to 30°C for 1.5
hours, then an additional 500 mL of water added in 30
minutes. The mixture was cooled to 5°C with an ice bath
and the pH adjusted from 3 to 5.5 (monitored using pH
strips) with the addition of 100 mL of aqueous 9.5M
sodium hydroxide (0.95 mol). Excess cyanide was
destroyed with the addition of household bleach. 25 mL
(0.020 mol) was added to achieve a negative starch iodide
test. The cold mixture (10°C) was filtered and the solid
washed with water until the rinse exhibited a neutral pH
(pH strips). The solid was dried at 60°C to a constant
weight of 111.48.
The isolated solid melted at 244°C to 246°C on
a Fisher Johns block. A methanol solution containing the
solid exhibited no absorption throughout the W region of
210 to 240 nm. IR (CHC13) cm-12222 (cyanide) , 1775
(lactone) , 1732 (3-keto) . 1H NMR (pyridine d5) ppm 0. 94
(s,3H), 1.23 (s,3H).
Example 21A
Scheme 1: Step 2: Preparation of 4'S(4'a),7'a-
Hexadecahydro-11'a-hydroxy-10'~3,13'~i-dimethyl-3',5,20'-
trioxospiro [furan-2 (3H) , 17' /3-
CA 02550897 1997-12-11
238
[4, 7] methano [17H] cyclopenta [a] phenanthrene] -5' ~i (2'H) -
carbonitrile.
Into a 200 gallon glass-lined reactor was
charged 50 kg of enamine 2_, approximately 445 L of 0.8 N
dilute hydrochloric acid and 75L of methanol. The
mixture was heated to 80°C for 5 hours, cooled to 0°C for
2 hours. The solid product was filtered to give 36.5 kg
of dry product diketone:
0 0
HCI, CH~OH, Hp0
80 ° C, 5h
Step 2 ,
O
Hl NMR (DMSO-d6) : 4.53 (1H, d, J=6) , 3.74 (2H,
m), 2.73 (lH,dd, J=14,7) 2.65-2.14 (8H, m), 2.05 (1H, t,
J=11), 1:98-1.71 (4H,m), 1.64 (1H, m), 1.55 (1H, dd,
J=13, 5), 1.45-1.20 (7H, m), 0.86 (3H,s),
Example 21B
Scheme 1: Steps 1 and 2: In Situ Preparation of
4 ' S ( 4 ' a ) , 7 ' a-Hexadecahydro-11 ' a-hydroxy-10 ' ~i , 13 ' ~i -
dimethyl-3' , 5, 20' -trioxospiro [furan-2 (3H) , 17' (3-
[4, 7] methano- [17H] cyclopenta [a] phenanthrene] -5' ~i (2'H) -
carbonitrile from lla-hydroxycanrenone.
s
CA 02550897 1997-12-11
239
Into a reactor fitted with a cooling condenser,
mechanical stirrer, heating mantle and controller, and
funnel was charged 100 g (280.54 mmol) of 11-
hydroxycanrenone prepared grepared as in the manner of
Example 1 followed by 300 mL of dimethylacetamide
(Aldrich). The mixture was stirred until the 11-
hydroxycanrenone dissolved. To this mixture was added
31.5 mL of 50% sulfuric acid (Fisher) which caused the
temperature of the resulting mixture to rise about 10°C
to 15°C. A sodium cyanide solution prepared by dissolving
31:18 g (617.20 mmol) (Aldrich) of sodium cyanide in 54
mL of deionized water was then. added to the lla-
hydroxycanrenone mixture over a 2 to 3 minute period.
The temperature of the resulting mixture rose about 20°C
to 25°C after addition of the sodium cyanide solution.
The mixture was heated to 80°C and maintained
at this temperature for 2-3 hours. Once HPLC analysis
indicated the reaction for the conversion of the lla-
hydroxycanrenone to the enamine was substantially
complete (greater than 98% conversion), the heat source
was removed. Without isolation of the enamine contained
in the mixture, an additional 148 mL of 50% sulfuric acid
was added to the mixture over a 3-5 minute period. Over
a 10 minute period 497 mL of deionized water was then
added to the mixture.
The mixture was heated to 102°C and maintained
at that temperature until approximately 500 g of
distillate had been removed from the mixture. During the
reaction/distillation, 500 mL of deionized water was
added to the mixture in four separate 125 mL portions.
Each portion was added to the mixture after an equivalent
amount of distillate (approximately 125 mL) had been
removed. The reaction continued for over 2 hours. When
HPLC analysis indicated that the reaction hydrolyzing the
enamine to the diketone was substantially completed
CA 02550897 1997-12-11
240
(greater than 98~ conversion), the mixture was cooled to
about 80°C over a 20 minute period.
The mixture was filtered through a glass
funnel. The reactor was rir_sed with 1.2 L of deionized
water to remove residual product. The solid on the
filter was washed three times using approximately equal
portions (about 0.4 L) of the rinse water. A 1 L
solution of methanol and deionized water (1:1 v/v) was
prepared in the reactor and the filtrate was washed with
500 mL of this solution. The filtrate was then washed a
second time with the remaining 500 mL of the
methanol/water solution. Vacuum was applied to the
funnel to dry the filtrate sufficiently for transfer.
The filtrate was transferred to a drying oven where it
Z5 was dried under vacuum for 16 hours to yield 84 g of dry
product diketone, 4'S(4'a),7'a-Hexadecahydro-11'a-
hydroxy-10'Q;13'Q-dimethyl-3',5,20'-trioxospiro[furan-
2 (3H).; 17' Vii- [4, 7] methano--[17H] cyclopenta [a] phenanthrene] -
5'~i(2'H)-carbonitrile. HPLC assay indicated 94% of the
desired diketone.
Example 22
Scheme 1: Step 3A: Method A: Preparation of
Methyl Hydrogen llcx,l7«-Dihydroxy-3-oxopregn-4-ene-7cx,21-
dicarboxylate, y-Lactone.
A 4-neck 5-L bottom flask was equipped with
mechanical stirrer, pressure equalizing addition funnel
with nitrogen inlet tube, thermometer and condenser with
bubbler. The bubbler was connected via tygon tubing to
two 2-L traps, the first of which was empty and placed to
prevent back-suction of the material in the second trap
(1 L of concentrated sodium hypochlorite solution) into
the reaction vessel. The diketone 3 (79.50 g; [weight
not corrected for purity, which was 85%]) was added to
the flask in 3 L methanol. A 25o methanolic sodium
CA 02550897 1997-12-11
241
methoxide solution (64.83 g) was placed in the funnel and
added dropwise, with stirring under nitrogen, over a 10
minute period. After the addition was complete, the
orangish yellow reaction mixture was heated to reflex for
2o hours. After this period, 167 mL of 4 N HC1 was added
(Caution: HCN evolution at this point!) dropwise through
the addition funnel to the still refluxing reaction
mixture. The reaction mixture lightened in color to a
pale golden orange. The condenser was then replaced with
a take-off head and 1.5 L of methanol was removed by
distillation while 1.5 L of water was simultaneously
added to the flask through the funnel, in concert with
the distillation rate. The reaction mixture was cooled
to ambient temperature and extracted twice with 2.25 L
aliquots of methylene chloride. The combined extracts
were washed successively with 750 mL aliquots of cold
saturated NaCl solution, IN NaOH and again with saturated
NaCl. The organic layer was dried over sodium sulfate
overnight, filtered and reduced in volume to -.250 mL in
vacuo. Toluene (300 mL) was added and the remaining
methylene chloride was stripped under reduced pressure,
during which time the product began to form on the walls
of the flask as a white solid. The contents of the flask
were cooled overnight and the solid was removed by
filtration. It was washed with 250 mL toluene and twice
with 250 mL aliquots of ether and dried on a vacuum
funnel to give 58.49 g of white solid was 97.3% pure by
HPLC. On concentrating the mother liquor, an additional
6.76 g of 77.1% pure product was obtained. The total
yield, adjusted for purity, was 78%.
H1 NMR (CDC13) : 5 . 70 (1H, s) , 4 .08 (1H, s) , 3 . 67
(3H,s), 2.9-1.6 (19H, m), 1.5-1.2 (5H, m), 1.03 (3H.s).
Example 23
Scheme 1: Step 38: Conversion of Methyl
Hydrogen l1a,17a-Dihydroxy-3-oxopregn-4-ene-7a,21-
CA 02550897 1997-12-11
242
dicarboxylate, y-Lactone to Methyl Hydrogen 17a-Hydroxy-
lla-(methylsulfonyl)oxy-3-oxopregn-4-ene-7a,21-
dicarboxylate, ~-Lactone.
A 5-L four neck flask was equipped as in the
above example, except that no trapping system was
installed beyond the bubbler. A quantity of 138.70 g of
the hydroxyester was added to the flask, followed by 1425
mL methylene chloride, with stirring under nitrogen. The
reaction mixture was cooled to -5°C using a salt/ice
bath. Methanesulfonyl chloride (51.15 g, 0.447 mole) was
added rapidly, followed by the slow dropwise addition of
triethylamine (54.37 g) in 225 mL methylene chloride.
Addition, which required -30 minutes, was adjusted so
that the temperature of the reaction never rose about
5°C. Stirring was continued for l hour post-addition,
and the reaction contents were transferred to a 12-L
separatory funnel, to which was added 2100 mL methylene
chloride. The solution was washed successively with 700
mL aliquots each of cold 1N HC1, 1N NaOH, and saturated
aqueous NaCl solution. The aqueous washes were combined
and back-extracted with 3500 mL methylene chloride. All
of the organic washes were combined in a 9-L jug, to
which was added 500 g neutral alumina, activity grade II,
and 500 g anhydrous sodium sulfate. The contents of the
jug were mixed well for 30 minutes and filtered. The
filtrate was taken to dryness in vacuo to give a gummy
yellow foam. This was dissolved in 350 mL methylene
chloride and 1800 mL ether was added dropwise with
stirring. The rate of addition was adjusted so that
about one-half of the ether was added over 30 minutes.
After about 750 mL had been added, the product began to
separate as a crystalline solid. The remaining ether was
added in 10 minutes. The solid was removed by
filtration, and the filter cake was washed with 2 L of
ether and dried in a vacuum oven at 50°C overnight, to
give 144.61 g (88%) nearly white solid, m.p. 149°-150°C.
CA 02550897 1997-12-11
243
Material prepared in this fashion is typically 98-99%
pure by HPLC (area %). In one run, material having a
melting point of 153°-153.5°C was obtained, with a
purity, as determined by HPLC area, of 99.5%.
Hl NMR (CDC13) : 5.76 (lH,s) , 5.18 (lH,dt) ,
3 . 68 (3H, s) , 3 . 06 (3H, s) , 2 . 85 (lH,m) , 2. 75-1. 6 (19H, m) ,
1 . 43 (3H, s) , 1. 07 (3H, s) .
Example 24
Scheme 1: Step 3C: Method A: Preparation of 7-
Methyl Hydrogen 17a-Hydroxy-3-oxopregna-4,9(11)-diene-
7a,21-dicarboxylate, 'y-Lactone.
A 1-L four neck flask was equipped as in the
second example. Formic acid (250 mL) and acetic
anhydride (62mL) were added to the flask with stirring
under nitrogen. Potassium formate (6.17 g) was added and
the reaction mixture was heated with an oil bath to an
internal temperature of 40°C (this was later repeated at
70°C with better results) for 16 hours.. After 16 hours,
the mesylate was added and the internal temperature was
increased to 100°C. Heating and stirring were continued
for 2 hours, after which the solvent was removed in vacuo
on a rotavap. The residue was stirred with 500 mL ice
water for fifteen minutes, then extracted twice with 500
mL aliquots of ethyl acetate. The organic phases were
combined and washed successively with cold 250 mL
aliquots of saturated sodium chloride solution (two
times), 1 N sodium hydroxide solution, and again with
saturated sodium chloride. The organic phase was then
dried over sodium sulfate, filtered and taken to dryness
in vacuo to give a yellowish white foam, which pulverized
to a glass when touched with a spatula. The powder that
formed, 14.65 g analyzed (by HPLC area %) as a mixture of
82.1% 7-Methyl Hydrogen 17a-Hydroxy-3-oxopregna-4,9(11)-
diene-7a,21-dicarboxylate, 'y-Lactone; 7.4~ 7-Methyl
Hydrogen 17a-Hydroxy-3-oxopregna-4,11-diene-7x,21-
CA 02550897 1997-12-11
244
dicarboxylate, 'y-Lactone; and 5:7% 9x,17-dihydroxy-3-oxo
17a-pregn-4-ene-7x,21-dicarboxylic acid, bis(y-lactone).
Hl NMR (CDC13) : 5.74 (1H, s) , 5.67 (lH,m) , 3.61
(3H,s), 3.00 (lH,m), 2.84 (1H, ddd, J=2,6,15), 2.65-2.42
(6H,m), 2.3-2.12 (SH;m), 2.05-1.72 (4H,m), 1.55-1.45
(2H,m) , 1.42 (3H, s) , 0. 97 (3H, s) .
Example 25
Scheme 1: Step 3C: Method B: Preparation of
Methyl Hydrogen 17a-Hydroxy-3-oxopregna-4,9(11)-diene
7x,21-dicarboxylate, 'y-Lactone.
A 5-L four neck flask was equipped as in the
above example and 228.26 g acetic acid and 41.37 g sodium
acetate were added with stirring under nitrogen. Using
an oil bath, the mixture was heated to an internal
temperature of 100°C. The mesylate (123.65 g) was added,
and heating was continued for thirty minutes. At the end
of this period, heating was stopped and 200 mL of ice
water was added. The temperature dropped to 40°C and
stirring was continued for 1 hour, after which the
reactiowmixture was poured slowly into 1.5 L of -cold
water in a 5-L stirred flask. The product separated as a
gummy oil. The oil was dissolved in 1 L ethyl acetate
and washed with 1 L each cold saturated sodium chloride
solution, 1 N sodium hydroxide, and finally saturated
sodium chloride again. The organic phase was dried over
sodium sulfate and filtered. The filtrate was taken to
dryness in vacuo to give a foam which collapsed to a
gummy oil. This was triturated with ether for some time
and eventually solidified. The solid was filtered and
washed with more ether to afford 79.59 g of a yellow
white solid. This consisted of 70.4% of the desired p
enester 6, 12.3 of the pll,lz enester 8, 10.8% of the 7-
cx,9-a-lactone 9 and 5.7% unreacted 5.
Example 26
CA 02550897 1997-12-11
245
Scheme 1: Step 3D: Method A: Synthesis of
Methyl Hydrogen 9,lla-Epoxy-17a-hydroxy-3-oxopregn-4-ene-
7a,21-dicarboxylate, y-Lactone.
A 4-neck jacketed 500 mL reactor was equipped
with mechanical stirrer, condenser/bubbler, thermometer
and addition funnel with nitrogen inlet tube. The
reactor was charged with 8.32 g of the crude enester in
83 mL methylene chloride, with stirring under nitrogen.
To this was added 4.02 g dibasic potassium phosphate,
followed by 12 mL of trichloroacetonitrile. External
cooling water was run through the reactor jacket and the
reaction mixture was cooled to 8°C. To the addition
funnel 36 mL of 30% hydrogen peroxide was added over a 10
minute period. The initially pale yellow colored
reaction mixture turned almost colorless after the
addition was complete. The reaction mixture remained at
9~1°C throughout the addition and on continued stirring
overnight (23 hours total). Methylene chloride (150 mL)
was added to the reaction mixture and the entire contents
were added to -250 mL ice water. This was extracted
three times with 150 mL aliquots of methylene chloride.
The combined methylene chloride extracts were washed with
400 mL cold 3% sodium sulfite solution to decompose any
residual peroxide. This was followed by a 330 mL cold 1
N sodium hydroxide wash, a 400 mL cold 1 N hydrochloric
acid wash, and finally a wash with 400 mL brine. The
organic phase was dried over magnesium sulfate, filtered,
and the filter cake was washed with 80 mL methylene
chloride. Solvent was removed in vacuo to give 9.10 g
crude product as a pale yellow solid. This was
recrystallized from -25 mL 2-butanone to give 5.52 g
nearly white crystals. A final recrystallization from
acetone (-50 mL gave 3.16 g long, acicular crystals, mp
241-243°C.
CA 02550897 1997-12-11
246
Hl NMR (CDC13) : 5 . 92 (1H, s) , 3 .67 (3H, s) , 3 .13
(lH,d,J=5), 2.89 (1H, m), 2.81-2.69 (lSH,m), 1.72 (1H,
dd, J=5, 15) , 1.52-1.22 (5H,m) , 1.04 (3H, s) .
Example 27
Scheme 1: Step 3: Option 1: From 4'S(4'a),7'a-
~Hexadecahydro-11' oc-hydroxy-10 ~ ~, 13' ~i-dimethyl-3' , 5, 20' -
trioxospiro[furan-2(3H),17'Q-
[4, 7] methano [17H] cyclopenta [a] phenanthrene] -5'/3 (2'H) -
carbonitrile to Methyl Hydrogen 9,llcx-Epoxy-17a-hydroxy-
3-oxopregn-4-ene-7x,21-dicarboxylate, 'y-Lactone.
Diketone (20 g) was charged into a clean and
dried reactor followed by the addition of 820 ml of MeOH
and 17.6 ml of 25% NaOMe/MeOH solution. The reaction
mixture was heated to reflex condition (-67°C) for 16-20
hours. The product was quenched with 40 mL of 4N HC1.
The solvent was removed at atmospheric pressure by
distillation. 100 mL of toluene was added and the
residual methanol was removed by azeotrope distillation
with toluene. After concentration, the crude
hydroxyester 4 was dissolved in 206 mL of methylene
chloride and cooled to 0°C. Methanesulfonyl chloride (5
mL) was added followed by a slow addition of 10.8 ml of
triethylamine. The product was stirred for 45 minutes.
The solvent was removed by vacuum distillation to give
the crude mesylate 5.
In a separate dried reactor was added 5.93 g of
potassium formate, 240 mL of formic acid and followed by
118 mL of acetic anhydride. The mixture was heated to
70°C for 4 hours.
The formic acid mixture was added to the
concentrated mesylate solution 5 prepared above. The
mixture was heated to 95-105°C for 2 hours. The product
mixture was cooled to 50°C and the volatile components
were removed by vacuum distillations at 50°C. The
product was partitioned between 275 ml of ethyl acetate
CA 02550897 1997-12-11
247
and 275 ml of water. The aqueous layer was back
extracted with 137 ml of ethyl acetate, washed with 240
ml of cold 1N sodium hydroxide solution and then 120 ml
of saturated NaCl. After phase separation, the organic
layer was concentrated to under vacuum distillation to
give crude enester.
The product was dissolved in 180 mL of
methylene chloride and cooled to 0 to l5°C. 8.68 g of
dipotassium hydrogen phosphate was added followed by 2.9
mL of trichloroacetonitrile. A 78 mL solution of 30%
hydrogen. peroxide was added to the mixture over a 3
minute period. The reaction mixture was stirred at 0-
15°C for 6-24 hours. After the reaction, the two phase
mixture was separated. The organic layer was washed with
126 mL of 3% sodium sulfite solution, 126 mL of 0.5 N
sodium hydroxide solution, 126 mL of 1 N hydrochloric
acid and 126 mL of 10% brine. The product was dried over
anhydrous magnesium sulfate or filtered over CeliteTM and
the solvent methylene chloride was removed by
distillation at atmospheric pressure. The product was
crystallized from methylethyl ketone twice to give 7.2 g
of epoxymexrenone.
a o
o ~~~~coocH~
.;
Epoxymex~ enone
O
DI ket one
CA 02550897 1997-12-11
248
Examflle ~8
Scheme 1: Step 3: Option 2: Conversion of
1' S (4' cx) , 7' a-Hexadecahydro-11' a-hydroxy-10' ~Q, 13 ' ~i-
dimethyl-3',5,20'-trioxospiro[furan-2(3H),17'~-
[4, 7] methano [17H] cyclopenta [a] phenanthrene] -5' ~ (2' H) -
carbonitrile to Methyl Hydrogen 9,31x-Epoxy-17a-hydroxy-
3-oxopregn-4-ene-7x,21-dicarboxylate; Y-Lactone without
intermediate isolation.
A 4-neck 5-L round bottom flask was equipped
with mechanical stirrer, addition funnel with nitrogen
inlet tube, thermometer and condenser with bubbler
attached to a sodium hypochlorite scrubber. The diketone
(83.20 g) was added to the flask in 3.05 L methanol: The
addition funnel was charged with 67.85 g of a 25% (w: w)
solution of sodium methoxide in methanol. With stirring
under nitrogen, the methoxide was added dropwise to the
flask over a 15 minute period. A dark orange/yellow
slurry developed. The reaction mixture was heated to
reflux for 20 hours and 175 mL 4 N hydrochloric acid was
added dropwise while refluxing continued. (Caution, HCN
evolution during this operation!) The reflux condenser
was replaced with a takeoff head and 1.6 L of methanol
was removed by distillation while 1.6 L of aqueous l0%
sodium chloride solution was added dropwise through the:
funnel, at a rate to match the distillation rate. The
reaction mixture was cooled to ambient temperature and
extracted twice with 2.25 L of aliquots of methylene
chloride: The combined extracts were washed with cold
750 mL aliquots of 1 N sodium hydroxide and saturated
sodium chloride solution. The organic layer was dried by
azeotropic distillation of the methanol at one
atmosphere, to a final volume of 1 L (0.5% of the total
was removed for analysis).
The concentrated organic solution
(hydroxyester) was added back to the original reaction
CA 02550897 1997-12-11
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COyiPREND PLUS D'UN TOLYIE.
CECI EST LE TOIYIE DE
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Brevets.
.IUMBO APPLICATIONS / PATENTS
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THAN ONE VOLUME.
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