Note: Descriptions are shown in the official language in which they were submitted.
~L~S7~313
Detailed Descrle~_on
This invention relates to ~-lactam antibiotics. More
specifically, it relates to the reaction of a penicillin
sulfoxide with an isocyanate to produce the corresponding
2-carbamoyloxymethylpenam, the corresponding 3-carbamoyloxy-
cepham or the corresponding 3-methylcep~em. In another
aspect, this invention relates to the cleavage of the above
products to produce the corresponding compounds having a free
amino group in t~e 6-position (penams) or 7-position (cephams
and cephems), and to the acylation of the free amino groups
of these latter compounds to produce still different 6-acyl-2-
carbamoyloxymethylpenams, 7-acyl-3-car~amoyloxycephams and
7-acyl-3-methylcephem3.
The reactions may be better visualized by referenca to
the following general reaction schemes.
R2/ ~H3 ~ CO)
oOR4
(I) (II)
Rl R3 CH20CNHR Rl R3 S
\ N ~ ~ H3 d R ~ 6
,O COOR O ~ ~ OCNHR
COOR
(III)
(IV)
..,
'
Rl R3
base N ~ ~
III or IV ~ O ~ CH3
COOR7
(V)
R3 CH20CNHR6
cleavage > H2N ~ ~ CH3
, 7
O COOR
(VI)
cleavage H2 ~ OCNHR6
COOR7
(VII)
cleavage ~ ~S ~
V ~ H2Nt~ 1
~ ~ 7CH3
COOR
(VIII)
acylation R3 S CH20CNHR6
VI _ > R -CN ~ ~ CH3
o~N '''CooR7
(IX)
~7~3
o ~3
acylation > R8-CNH;; ~ ~HR6
COOR7
IX)
ylat~on 8 11 ~ S ~
O ~ C~3
CooR7
(XI)
In the above general reaction schemes,
Rl is hydrogen and
R2 i5 an amino-blocking group or a conventional acyl
group known in the penicillin or cephalosporin art, or
Rl and R2, taken together with the nitrogen to which
they are attached, may form a phthalimido group, a succinimido
group or a group of the formula
Rll o
R12_~; N--
R?<Rl o
~ ~7~13
in which R and R are (lower)alkyl, R is 1,4-cyclo-
hexadienyl, substituted or unsubstituted phenyl, or a
substituted or unsubstituted heterocyclic group containing
one or more hetero atoms such as sulfur, oxygen and/or
nitrogen, e.g. thienyl, furyl, tetrazolyl, thiazolyl or
thiadiazolyl; and R12 is hydrogen, an aldehydo group
or a nitroso group;
R3 is hydrogen, tlower)alkoxy, (lower)alkylthio or
R13~H- in which ~13 is substituted or unsubstituted (lower)-
OH
alkyl or aryl;
-CooR4 is a protected carboxyl group or a derivative
o a carboxyl group;
R5 is an acyl group, a thioacyl group, a substituted
sulfonyl, sulfinyl or sulfenyl group, or a substituted
metal or non-metal atom having a valence of from 2 to 5;
n is an integer of from 1 to 4;
R6 is hydrogen, is the same as ~5, or is
~;i7~13
~Coil2c~\ 2
COOR
-R5 (XII)
\ O ~_N/
COO~
in which Rl, R2, R3 and R7 are as defined above, and a and
b are the same or different and represent an integer ~rom
O to n-1, wherein n is as defined above, provided that the
sum of a and b is not greater than n-l;
R7 's hydrogen or the same as R4; and
R -C- is a conventional acyl group known in the
penicillin and cephalosporin art.
:`
:
~. -6-
i'
~57~3
In this divisional application the invention provides
a process for the preparation of a compound of the formula
~ N ~ S
- 0 ~ ~ CH
C90R
wherein
~1 is hydrogen and
~ 2 is hydrogen, an amino-protecting group or an acyl
group; or
Rl and R2, taken together with the nitrogen to which
they are ~ttached, form a phthalimido group, a succinimido
group or a group of the formula
R12_ ~ N
/\
R9 R10
in which R9 and R10 are (lower)alkyl, Rll is 1,4-cyclo-
hexadienyl, substituted or unsubstituted phenyl, or a
~ubstieuted or unsubstituted heterocyclic group, and nl2
i5 hydrogen, an aldehyde group or a ni~roso group;
; -6(a)-
~5~ 3
R3 is hyd~ogen~ (lower)alkoxy, (lower)alkylthio or
R13C~ (OH) ;~ in which R13 is substi~u~ed s:)r u:nsubsti~uted
~lower)alkyl, or substituted or unsubstituted aryl; and
~ OOR is ~COOHo a pro~ected ~:arbos:yl group or a
desivative of a ~arboxyl group;
which procass comprise~ rea ting a compou~d of th~ fDrmula
R ~ 3
~OOR
in ~hich Rl, R2 and ~3 ~re as deflned a~ove and coo~4 iB a
protec ted c~rboxyl group or ~ d erivative of a carbo~;yl group;
at a tem~erature up to about 200 g in {~ lnert organic sol~ent,
~ith ~t lea~t an equi~olar amount of an lsocyans,te of the
~os7nula
R5 ~NCO )n
dh~rein ~5 ~ an a~yl group, a thioacyl group, a ~ub~tituted
~ulfonylg sul~inyl or ~ enyl group~ or a ~ub tituted metal
or ~on-met~l atom ha~ring a valence ~ frola 2 to 5, ~nd n is
an int~ger o~ 1 to 4; in tAe presence of ~n organic bl~e or
an inorganlc lbase ~rhich ~s ~oluble ln the organic ~olv~nt,
OEt an ~lkalisle pH; and, lf P~7 is not hydrogen, optlon~lly
conYerting GoOR7 to a carbo~l grou~ by a conventlonal
oetbod .
-6 (b)-
i7~3~3
The isocyanates of Formula II, above, include, for
e~ample, those of the following formulae.
(a) W2 M2 NCO
in which ~2 is a divalent metal or non-metal atom (and
preferably sulfur or selenium) and ~2 is a substituted or
unsubstituted alkyl, aryl or aralkyl group, or an isocyanate
group. Examples of isocyanates falling within this class
are trichloromethylsulfenyl isocyanate, di~hloromethylsulfenyl
isocyanate, trifluoromethylsulfenyl isocyanate, difluoro-
methylsulfenyl isocyanate, 2,4- dinitrophenylsulfenyl isocyanate,
sulfenyl diisocyanate, selenium diisocyanate, chloromethyl
selenium isocyanate, dichloromethyl .qelenium isocyanate
trichloromethyl selenium isocyanate, mono-, di- or trifluoro-
methyl selenium isocyanate, and the like.
W3 ~
(b) ~ M3-NCO
x3
in which M3 is a trivalent metal or non-metal atom, ~3 and
X3 are the same or different and represent a substituted or
unsubstituted (lower)alkyl, aryl, ar(lower)alkyl, cycloalkyl,
(lower)alkoxy, aryloxy, ar(lower)alkoxy, (lower)alkylthio,
or ar~lower)alkylthio group, or an isocyanate group; or
W3 and X3, taken together with ~13, r~present a ring system.
Examples of isocyanates falling within this class are
phosphorous triisocyanate, boron trlisocyanate, antimony
triisocyanate, aluminum triisocyanate, (C4Hg)2BNCO,
(C2H~)2~lNCO, C4HgB(NCO)2, C2H5Al(NC0)2, (C6H~)2PNCO,
--7--
~57~3
(C H 0)2BNCO, (C6H5CH20)2PNCO, (C2~5S)2P , 3 2
Clcx2c~2op(NcO)2~
CH2 - IH3
¦ P -NCO , CH -O ~
CH2 -O / 1 ~P -NCO
~( CH2~ [~C
and the like.
w4 \
(c) X4/ M4 NC~
in which M4 is a tetravalent metal or non-metal atom, W4,
X4 and Y4 are the same or different and represent a
substituted or unsubstituted llower)alkyl, aryl, ar(lower)-
alkyl, cycloalkyl, (lower)alkoxy, aryloxy, ar(lower)alkoxy,
(lower)alkylthio, or ar(lower)alkylthio group, or an
isocyanate group; or W4 and X4, taken together with M4,
i represent a ring system; or W4, X4 and Y4, taken together
with M4, represent a ring system other than phenyl or
substituted phenyl; or W4 and X4, taken together, represent
: =0, -S or =NW4. Examples of isocyanates within this class
are:
',`
-8-
7~3
(1) acyl isocyanates and thioacyl isocyanates such as
acetyl isocyanate, mono-, di- or trichloroacetyl isocyanate,
mono-, di- or trifluoroacetyl isocyanate, propionyl and
butyryl isocyanates and their chlorinated or fluorinated
analogs, phenylacetyl isocyanate, cyanoacetyl isocyanate,
benzoyl isocyanate, p-nitrobenzoyl isocyanate, 2,4-dinitxo-
benzoyl isocyanate, benzyloxycarbonyl isocyanate, p-nitro-
benzyloxycarbonyl isocyanate, methoxycarbonyl isocyanate,
chloromethoxycarbonyl isocyanate, carbonyl diisocyanate,
cyanocarbonyl isocyanate, and the like,as well as their
thio analogs, e.g. trichlorothioacetyl isocyanate, chloro-
methoxythiocarbonyl isocyanate, and the like;
~ 2) sulfinyl isocyanates of the formula
Y4 - S - NCO
in which Y4 is as defined above;
(3) metal and non-metal tetraisocyanates such as
Sn(NCO)4, Se(NCO)4, Ti(NCO)4, Ge(NCO)4, Si(NCO)4, and the
like;
(4) substituted metal and non-metal isocyanates of
the formula
W4a~
X4a ~ M4 - NCO
Y4a
in which M4 is as defined above and W4a, X4a and Y4a are
the 3ame or different and represent substituted or unsubstituted
(lower)alkyl, (lower)alkoxy or (lower)alkylthio; or W4a or
7~3
both r~4a and X4a, may be an isocyanate group; or W4a and
X4a, taken together with M4, may represent a ring system.
Examples of isocyanates falling within this class axe
(CX3)3SnNCO, ~C~3)3SbNCO, (CH3)3GeNCO, (CH3)3TiNCO,
3 2 ( )2~ (CH3)2Sb~NC0)2, CH3Ti(NCo)3, CH3Ge(NCO)
2 5 3 , (C2H50)3SbNCO, (C2H55)3TiNCO, (c2H~s~3GeNco
(ClC2H4)3ShNCO,
1 2 5b'~' f~2 ~ s NCO
C~2__~' NCO , CH2 ~ NCO
and the like;
(5) silyl isocyanates of the formula
~W4)m - Si (NCO)4-m
in which W4 i5 as described above and m is an integer of
from 1 to 3. Examples of isocyanates falling within this
class include trimethylsilyl isocyanate, d~methylsilyl
diisocyanate, methylsilyl triisocyanate, trimethoxysilyl
isocyanate, triethoxysilyl isocyanate, triethylsilyl
isocyanate, diphenylsilyl diisocyanate,dibenzyloxy
diisocyanate,triphenylsilyl isocyanate, tribenzylsilyl isocyanate,
(ClC2H4)3SiNCO, (ClC2H40)2Si(NC0)2, (C6H50)2Si(N~0)2,
CH3 Si - NCO CH3___ _ _,, NCO
C~30 ~ NCO , C2H50~'' ~ NCO
--10--
~7~ 3
C2~50 CH3 \
CH3 / SiNCO , C4Hg - SiNCO
C2~50 CH3
and the like; and
~6) ring compounds of the formula
~ 3a\
OC~-C C-NCO
3a / 3a
~C
NCO
in which M3a is nitrogen, boron, phosphorus or antimony.
(d) / M5- NCO
Z5
in which ~S is a pentavalent metal or non-metal atom and
W5, X5, Y5 and ZS are the same or different and represent
a substituted or unsubstituted (lower)alXyl, aryl, aryloxy,
(lower)alkoxy, or (lower)alXylthio group, or an isocyanate
group; or W5 and X5, taken together with M5, represent a
ring system; or W5 and X5, taken together, represent =0 or
-S. Examples of isocyanates within this class are
(C4H9)3Sb(NC0)2, (CH3)4SbNCO, (ClC2H4)3Sb~NC0)2,
~i7~313
C~30P~NCO)2 ~ P(NC0)3 , ~ P~NC0)2
o CH3 \ IJ C2H5 \ ll
Clc2H40P(NC0)2 ~ / PNC0 , / PNC0
CH3 C~H50
CH30 \ S C2H~S \ e O
/ PNC0 , / PNC0 , ~ OP(NC0)2
CH30 C2H5S
P(NC0)3 , and the like.
~e) R14 - S - NC0
,
in which R14 is a substituted or unsubstituted ~lower)alkyl,
aryl, ar(lower)alkyl, cycloalkyl, (lower)alkoxy, aryloxy,
ar(lower)alkoxy, (lower)alkylthio, or ar(lower)al~ylthio
group, or an isocyanate group. Examples of isocyanates
falling within this class are methylsulfonyl isocyanate,
chloromethylsulfonyl isocyanate, phenylsulfonyl isocyanate,
p-nitrophenylsulfonyl isocyanate, 2,4-dinitrophenylsulfonyl
isocyanate, toluenesulfonyl isocyanate, phenoxysulfonyl
isocyanate, benzyloxysulfonyl isocyanate, ethoxysulfonyl
isocyanate, ethylthiosulfonyl isocyanate, sulfonyl diisocyanat2,
and the like.
-12-
~L~57i~3
In one preferred embodiment of the invention, in
the penicillin sulfoxide ester starting material of ~ormula
I, Rl and R2, taken together with the nitrogen to which
they are attached, may form a phthalimido group, a succinimido
group or a group of the formula
Rll o
R12~
R9 ~ R
in which R9 and R10 are (lower)alkyl, Rll is 1,4-cyclo-
hexadienyl, substituted or unsubstituted phenyl, or a
~ubstituted or unsubstituted heterocyclic group containing
one or more hetero atom~ such as sulfur, oxygen and~or
nitrogen, e.g. thienyl, furyl, tetrazolyl, thiazolyl or
thiadiazolyl, and R12 is hydrogen, an aldehydo group or a
nitroso group.
In a more preferred embodiment Rl and R2, taken
together with the nitrogen to which they are attached, form
a group of the formula
Rll o
R12_ N N--
R9>~Rl O
~57~3
iXI which R9 and R10 are as defin~d above (but preferably
are each methyl), R 2 is as defined above (but preferably
is hydrogen, and Rll is as defined above tbut preferably
i3 1, 4-cyclohexadienyl, phenyl, p-hydroxyphenyl, thienyl,
furyl, tetrazolyl, thiazolyl or thiadiazolyl). Most
preferably, Rll is phenyl or p-hydroxyphenyl, It is also
preferred that R6 be hydrogen.
In another preferred embodiment of the invention,
in the penicillin sulfoxide ester starting material of
Formula I, R is hydrogen and R is an acyl group of the
formula
Rl~-(A)r(c~2)s(lH)t (XIV)
R16
in which r is O or 1, s i5 an integer of from O to 6, t is
O or 1, A is oxygen or sulfur, R16 is amino, substituted
amino, acylamino, hydroxy, azido, halogen, carboxy, caxbamoyl,
guanidino, sulfo, sulfamino, phosphono, acyloxy, tetrazolyl,
carboalkoxy, or the like, and R15 is hydrogen, or a substituted
or unsubstituted alkyl, aryl, aralkyl,cycloalkyl, heterocyclyl
or heterocyclylalkyl group.
In a more preferred ~ bodiment, the acyl group of
Formula XIV has the structure
O
R15 C- (XV)
in which R15 is as defined a~ove. Group R 5 may be unsubstituted
or may be substituted by such groups as OH, Sll, SR (where R
is alkyl or aryl), alkyl,alkoxy, aryl, halo, cyano, carboxy,
nitro, sulfoamino, carbamoyl, sulfonyl, azido, amino,
substituted amino, haloalkyl, carboxyalkyl, carbamoylalkyl,
7~3
N-csubstituted carbamoylalkyl, guanidino, N-substituted
guanidino, guanidinoalkyl, or the like. Examples of
su:Ltable acyl groups of Formula XV are those in which
R15 ic~ benzyl, p-hydroxybenzyl, 4-amino-4-carboxy~utyl,
methyl, cyanomethyl, n-amyl, n-heptyl, ethyl, propyl,
isopropyl, 3- or 4-nitrobenzyl, phenethyl, ~,B-diphenyl-
ethyl, methyldiphenylmethyl, triphenylmethyl, 2-methoxy-
phenyl, 2,6-dimethoxyphenyl, 2,4,6-trimethoxyphenyl, 3,5-
dimethyl-4-isoxazolyl, 3-butyl-5-methyl-4-isoxazolyl, 5-
methyl-3-phenyl-4-isoxazolyl, 3-(2-chlorophenyl)-5-methyl-
4-isoxazolyl, 3-(2,6-dichlorophenyl)-5-methyl-4-isoxazolyl,
2- or 3- (5-methylthienyl)methyl, D-4-amino-4-
carboxybutyl, D-4-N-benzoylamino-4-carboxy-n-butyl, p-amino-
benzyl, o-aminobenzyl, m-aminobenzyl, (3-pyridyl)methyl, 2-
ethoxy-l-naphthyl, 3-car~oxy-2-quinoxalinyl, 3-(2,6-dichloro-
phenyl)-5-(2-furyl)-4-isoxazolyl, 3-phenyl-4-isoxazolyl, 5-
methyl-3-(4-quanidinophenyl)-4-isoxazolyl, 4-guanidinomethyl-
phenyl, 4-guanidinomethylbenzyl, 4-quanidinobenzyl, 4-
guanidinophenyl, 2,6-dimethoxy-4-guanidinophenyl, o-sulfobenzyl,
p-carbcxymethylbenzyl, p-carbamoylmethylbenzyl, m-fluorobenzyl,
m-bromobenzyl, p-chlorobenzyl, p-methoxy~enzyl, l-naphthyl-
methyl, 3-isothiazolylmethyl, 4-isothiazolylmethyl, 5-iso-
thiazolylmethyl, 4-pyridylmethyl, 5-isoxazolylmethyl, 4-methoxy-
5-isoxazolylmethyl, 4-methyl-5-isoxazolymethyl, l-imidazolyl-
methyl, 2-benzofuranylmethyl, 2-indolylmethyl, 2-phenylvinyl,
2-phenylethynyl, 2-(5-nitrofuranyl)~inyl, phenyl, o-methoxy-
phenyl, o-chlorophenyl, o-phenylphenyl, p-aminomethylbenzyl,
1-~5-cyanotriazolyl)methyl, difluoromethyl, dichloromethyl,
dibromomethyl, 1-(3-methyllmidazolyl)methyl, 2- or 3-(5-
carboxymethylthienyl)methyl, 2-- or 3-(4-car~amoylthienyl)methyl,
-15-
~ 57~3
2-- or 3-(5-methoxythienyl)methyl, 2- or 3-(4-chlorothienyl~-
methyl, 2- or 3-(5-sulfothienyl~methyl, 2- or 3-(5-carboxy-
thienyl)methyl, 3-(1,2,5-thiadiazolyl)methyl, 3-(4-methoxy-
1l~2,5-thiadiazolyl)methyl, 2-furylmethyl, 2-(5-nitrofuryl)-
methyl, 3-furylmethyl, 2-thienylmethyl, 3-thienylmethyl,
tetrazolylmethyl, cyclopentyl, cyclohexyl, cycloheptyl
cyclohexylmethyl, cyclohexylpropyl, dihydrobenzyl, dihydro-
phenylmethyl, tolylmethyl, xylylmethyl, te~rahydronaphthyl-
methyl, piperazinylmethyl, pyrrolidiny~methyl, benzothiazolyl-
methyl, benzoxazolylmethyl, and lH (or 2H)-tetrazolylmethyl.
In another more preferred embodiment, the acyl group
of Formula XI~ has the structure
o
R15A(CH2)sC- (XVI)
wherein R15, A and s are as defined above. Examples of
suitab}e groups of the formula R15AtCH2)~- include methoxy-
methyl, methylthiomethyl, cyclohexylthiomethyl, cyclohexyloxy-
methyl, dihydrophenoxymethyl, dihydrophenylthiomethyl, cyclo-
pentyloxy, cyclohexyloxy, dihydrophenoxy, benzyloxy, xylyloxy,
tolyloxy, naphthoxy, phenylthiomethyl, butylmercaptomethyl,
allylthiomethyl, 2-furyloxy, 8-quinolyloxy, pyridylmethoxy,
trichloroethoxy, l-cyclopropylethoxy, p-nitrobenzyloxy,
o-chlorobenzyloxy, o-nitrobenzyloxy, p-methoxybenzyloxy, 3,4-
dimethoxybenzyloxy, a-chlorocrotylmercaptomethyl, phenoxy-
methyl, phenoxyethyl, phenoxybutyl, phenoxybenzyl, diphenoxy-
methyl, dimethylmethoxymethyl, dimethylbutoxymethyl, dimethyl-
phenoxymethyl, 4-guanidinophenoxymethyl, 4-pyridylthiGmethyl,
p-~carboxymethyl)phenoxymethyl, p-(carboxymethyl)phenylthio-
methyl, 2-thiazolylthiomethyl, p-(sul~o)phenoxymethyl,
-16-
~57~3
p (carboxy)phenylthiomethyl, p-5carboxymethyl)phenoxymethyl,
p~-(carboxymethyl)phenylthiomethyl, 2-pyrimidinylthiomethyl,
phenethylthiomethyl and l-(5,6,7,8-tetrahydronaphthyl)-
oxomethyl.
In another morP preferred embodiment, the acyl group
of Formula XIV has the structure
Rl CH-C- (XVII)
l16
wherein R15 and R16 are as defined above. Examples of suitable
groups of the formula
R15_c~_
116
include a-aminobenzyl, a-amino-2-thienyl, a-methylamino-
benzyl, a-amino-methylmercaptopropyl, a-amino-3- or 4-
c~lorobenzyl, a-amino-3 or 4-hydroxybenzyl, -amino-2,4-
dichlorobenzyl, aoamino-3,4-dichlorobenzyl, ~(-)-a-hydroxy-
benzyl, a-carboxybenzyl, a-amino-3-thienyl, a-aminO-2-
thienyl, D-(-)-a-amino-3-chloro-4-hydroxybenzyl, D(-)-a-
amino-3-thienyl, l-aminocyclohexyl, a-(5-tetrazolyl)benzyl,
2-(a-carboxy)thienylmethyl, 3-(a-carboxy)furylmethyl,
a-sulfaminobenzyl, a-sulfamino-3-thienyl, a-(N-methylsulfamino)-
benzyl, D(-)-a-yuanidino-2-thienyl, D(-)-a-guanidinobenzyl,
a-guanylureidobenzyl, a-hydroxybenzyl, a-azidobenzyl, a-fluoro-
benzyl, 4-(5-methoxy-1~3-oxadiazolyl)-amlnCmQthyl~ 4-(5-methoxy-
1,3-oxadiazolyl)-hydroxymethyl, 4-(5-methoxy-l~3-oxadiazolyl)
carboxymethyl, 4-t5-methoxy-1,3-sulfadiazolyl)-aminomethyl,
4-~(5-methoxy-1,3-sulfadiazolyl)-hydroxymethyl, 4-(5-methoxy-
1,3-sulfadiazolyl)-carboxymethyl, 2-(5-chlorothienyl)-amino-
methyl, 2-(5-chlorothienyl)-hydroxymethyl, 2-(5-chlorothienyl)~
carboxymethyl, 3-(1,2-thiazolyl)-aminomethyl, 3-(1,2-thiazolyl)-
hydroxymethyl, 3-(1,2-thiazolyl)-carboxymethyl, ~-(1,4-thiazolyl)-
aminomethyl, 2-(1,4-thiazolyl)-hydroxymethyl, 2-(1,4-thiazolyl)-
carboxymethyl, 2-benzothienylaminomethyl, 2-benzothienyl-
hydroxymethyl, 2-benzothienylcarboxymethyl, a-sulfobenzyl, and
a-phosphonobenzy~
I~ the acyl group contains a functional group, such
as amino, hydroxy, mercapt~ or carboxy, the functional
group may be protected with an appropriate protective group.
Because the acyl side-chain may subsequently be cleaved to
produce the free amino compound (which may, if desired, be
re-acylated with a different side-chain), it is not always
necessary to protect reactive substituent groups in the
side-chain.
Suitable protective groups for the amino radical include
any of the conventional protective groups such as those acyl
groups which can easily be split off (e.g. trichloroethoxy-
carbonyl, benzyloxycarbonyl, p-toluenesulfonyl, p-nitrobenzyl-
oxycarbonyl, o-chlorobenzyloxycarbonyl, o-nitrophenylsulfenyl,
chloroacetyl, trifluoroacetyl, formyl, tert-butoxycarbonyl,
p-methoxybenzyloxycarbonyl, 3,4-dimethoxybenzyloxycarbonyl,
4-phenylazobenzyloxycarbonyl, 4-(4-methoxyphenylazo)benzyloxy-
carbonyl, pyridine-l-oxide-2--methoxy-carbonyl, 2-pyridyl-
~ 18-
;7~3
methoxycarbonyl, 2-furyloxycarbonyl, diphenylmethoxycarbonyl,
l,1-dLmethylpropoxycarbonyl, isopropoxycarbonyl, l-cyclo-
pxopylethoxycarbonyl, phthaloyl, succinyl, 1-adamantyloxy-
carbonyl or 8-quinolyloxycarbonyl), or other radicals which
can easily be split off (e.g. trityl, 2-nitrophenylthio,
2,4-dinitrophenylthio, 2-hydroxybenzylidene, 2-hydroxy-5-
chlorobenzylidene, 2-hydroxy-1-naphthylmethylene, 3-hydroxy-
4-pyridylmethylene, 1-methoxycarbonyl-2-propylidene, l-ethoxy-
carbonyl-2-propylidene, 3-ethoxycarbonyl-2-butylidene, l-acetyl-
2-propylidene, 1-benzoyl-2-propylidene, 1-[N-(2-methoxyphenyl)-
carbamoyl]-2-propylidene, 1-[~-(4-methoxyphenyl)carbamoyl~-
2-propylidene, 2-ethoxycarbonylcyclohexylidene, 2-ethoxy-
carbonylcyclopentylidene, 2-acetylcyclohexylidene, 3,3-dimethyl-
5-oxocyclohexylidene, or mono- or bis-trialkylsilyl). Other
coAventional amino protecting groups such as those described
in ~Protective Groups in Organic Chemistry, n J. F . W. McOmie,
Ed., Plenum Press, New York, ~ew Yor~, 1973 Chapter 2, shall
be recognized as suitable.
Suitable protective groups for the hydroxy or mercapto
groups include any of the conventional protective groups for
hydroxy or mercapto groups such as the acyl groups which can
be easily split off ~e.g. benzyloxycarbonyl, 4-nitrobenzyloxy-
carbonyl, 4-methoxybenzyloxycarbonyl, 3,4-dLmethoxybenzyloxy-
carbonyl, 4-phenylazobenzyloxycarbonyl, 4-~4-methoxyphenylazo~-
benzyloxycarbonyl, tert-butoxycarbonyl, 1,l-dimethylpropoxy-
carbonyl, isopropoxycarbonyl, l-adamantyloxycarbonyl,
l-cyclopropylethoxycarbonyl, 8-quinolylethoxycarbonyl, 2,2,2-
trichloroethoxycarbonyl, 3-iodopropoxycarbonyl, 2-furfuryloxy-
--19--
carbonyl, 8-quinolyloxycarbonyl and trifluoroacetyl) and those
protecting groups other than acyl groups which can be
easily split off, such as benzyl, trityl, methoxymethyl,
2-nitrophenylthio and 2,4-dinitrophenylthio. Other
conventional hydroxy and mercapto protecting groups,
including those described in ~rotective Groups in Organic
Chemistry~, supra, Chapters 3 and 7, shall be considered
as suitable.
The protective group for the car~oxy group may be any
of those conventional protective groups used for protecting
a carboxy group, e.g. an ester group such as methyl, ethyl,
propyl, isopropyl, tert-butyl, butyl, benzyl, diphenylmethyl,
tri~henylmethyl, p-nitrobenzyl, p-methoxybenzyl, benzoylmethyl,
acetylmethyl, p-nitrobenzoylmethyl, p-chlorobenzoylmethyl,
p-methane~ulfonylbenzoylmethyl, phthalimidomethyl, trichloro-
ethyl, 1,1-dimethyl-2-propynyl, acetoxymethyl, propionyloxy-
methyl, pivaloyloxymethyl, 1,l-dimethylpropyl, 1,l-dimethyl-
2-propenyl, 3-methyl-3-butenyl, succinimidomethyl, l-cyclo-
propylethyl, 3,5-di(tert)butyl-4-hydroxybenzyl, methyl-
sulfenylmethyl, phenylsulfenylmethyl, methylthiomethyl,
phenylthiomethyl, dimethylaminomethyl, 2-methoxquinoline-1-
oxide, 2-methylpyridine-1-oxide, chlorooxalyl or di(p-methoxy-
phenyl)methyl ester, the silyl ester groups derived from a
silyl compound such as dimethyldichlorosilane twhich have
been reported in U. S. Patent 3,944,545, in Japanese Patent
Application No. 7332/1971 laid open to public inspection
under No~ 7073/1971 and in Netherlands Patent Application
laid open to public inspection under No. 7,105,259),
-20-
and metallic or non-metallic derivatives of the carboxy
group derived from such compounds as boron trichloride,
~C2H5)2AlCl, ~C~3O)2PCl and the like ~hich have been
disclosed in U. X. Patent 1,409,415. Other known conventional
carboxyl protecting groups such as those described in
"Protective Groups in Organic Chemistry", supra, Chapter 5,
shall be recognized as suitable.
In compound I, above, -COOR is defined as a protected
carboxyl group or a derivative of a carboxyl group. Suitable
car~oxyl-protecting groups are well known in the art, and
include those listed above for protecting carboxyl substituents
on the acyl side-chain. R4 also may be a metallic or non-
metallic derivative such as described above for protecting
carboxyl substitutents. The group -CooR4 preferably is
(1) an ester: a silyl ester such as referred to above,
an alkyl or alXenyl (e.g.~ methyl, ethyl, propyl, isopropyl,
butyl, tPrt-~utyl, cyclohexyl, cycloheptyl, vinyl, l-propenyl,
2-propenyl or 3-butenyl) ester, aryl (e.g., phenyl xylyl,
tolyl or naphthyl) ester, aralkyl (e.g., benzyl or diphenylmethyl)
ester, or an ester wherein one of the car~on atoms of the
alkyl group is replaced with a nitrogen, sulphur or oxygen
atom, or by a carbonyl group, such as methoxymethyl ester,
ethoxymethyl ester, methylthioethyl ester, methylthiomethyl
ester, dimethylaminoethyl ester, diethylaminoethyl ester,
phenoxymethyl ester, phenylthiomethyl ester, methylsulfenyl-
methyl ester, phenylsulfenyLmethyl ester, benzoylmethyl ester
or toluoylmethyl ester, or an ester containing one or more
appropriate substituents (e.g., halogen, alkoxy, alkanesulfonyl
or phenylazo) such as chloromethyl ester, bromomethyl ester,
-21-
~7~3
trichloroethyl ester, cyanomethyl ester, p-nitrophenyl ester,
2,4,5-trich}orophenyl ester, 2,4,6-trichlorophenyl ester,
pentachlorophenyl ester, p-methylsulfon~lphe~l estar, 4-
phenylazophenyl ester, 2,4-dinitrophenyl ester, p-chlorobenzyl
ester, o-nitrokenzyl ester, p-methoxybenzyl ester, ponitrobenzyl
ester, 3,4,5-trimethoxybenzyl ester, bis~p-methoxyphenyl)methyl
ester, pentachlorobenzyl ester, trichlorobenzyl ester, 3,5-
dittert)butyl-4-hydroxybenzyl ester, p-nitrophenylthiomethyl
ester, p-nitrobenzoylmethyl ester or p-chlorobenzoylmethyl
ester, or an ester formed from a thioalcohol, a substituted
thioalcohol, N-hydroxysuccinimide, N-hydroxyphthalimide,
tetrahydrofuran, l-cyclopropylethanol, l-phenyl-3-methyl-5-
pyrazolone, 3-hydroxypyridine, 2-hydroxymethylpyridine-1-
oxide, l-hydroxy-2(1~)-pyridine, dimethylhydroxyamine,
diethylhydroxyamine, glycolamide, 8-hydroxyquinoline, 2-
hydroxymethylquinoline-l-oxide, methoxyacatylene,
ethoxyacetylene, tert-butylethynyldimethylamine, tert-
butylethynyldiethylamine, ethylethynyldiethylamine or 2-
ethyl-5-(3-sulfophenyl)isoxazolium hydroxide inner salt;or
(2) an acid amide: an N-al~yl acid amide (e.g., N-
methyl acid amide or N-ethyl acid amide), N,N-dialkyl acid
amide (e.g., N,N-dimethyl acid amide, N,~-diethyl acid amide
or N-methyl-N-ethyl acid amide), or an acid amide with
Lmidazole, benzotriazole, a 4-substituted imidazole or a
protected tetrazole.
Other known conventional carboxy protecting groups such
as those described in nProtective Groups in Organic Chemistry",
supra, Chapter 5, shall be recognized as suitable.
The reaction of the penicil}in sulfoxide (I) with
thle isocyanate (II) is conducted in an inert organic solvent
such as dioxane, toluene, xylene, benzene, tetrahydrofuran,
methyl isobutyl ketone, 1,2-dichloroethane, methyl chloroform
or the like. The reaction may, if desired, be conducted in
excess isocyanata as the solvent. Dioxane is a preferred
solvent.
The reaction may be conducted over a wide temperature
range, e.g. up to about 200, preferably from about 70 to
about 140 and most preferably from about 90 to about 115.
It is most convenient to conduct the reaction at the reflux
temperature of a suitably selected solvent.
The reaction time is not critical and may range from
1 hour to 24 hourq, or more, depending on the particular
reactants, reaction temperature, etc.. In general, we prefer
to conduct the reaction for from about 1 to about 10 hours,
and typically from about 3 to about 7 hours.
The penicillin sulfoxide (I~ is reacted with at least
one equivalent of the isocyanate (II) and preferably with
an excess thereof, Up to about 5 equivalents, or more, of
isocyanate may be utilized, but no advantage is obtained
by using greater amounts. The isocyanate aids in maintaining
an anhydrous reaction medium by scavenging any free water
which may be present. We prefer to use from about 2 to 4
equivalents of the isocyanate, and most preferably about 3
equivalents of the isocyanate, per equivalent of the penicillin
3ulfoxide.
If the reaction of the penicillin sulfoxide (I) and the
isocyanate (II) is conducted in the absence of a base the
product is primarily a mixture of the penam (III) and the
-23-
~7~`~3
cepham ~IV), along with a small amount o~ the cephem (V~.
Thle xatio of the penam and cepham in the product may be
varied by the use of different isocyanates. Thus, for
example, when the p-nitrobenzyl ester of penicillin V
sulfoxide is reacted in dioxane with silicon tetraisocyanate,
the product usually consists of 95-98% of the penam and traces
of the cepham. ~lowe~er, the reaction of the p-nitrobenzyl
ester of penicillin V sulfoxide in dioxane with trichloroacetyl
isocyanate gives a product which typically is 30-35~ penam,
60-65% cepham and about S~ cephem. The product mixture may
readily be separated into its components by chromatography,
e.g. on silica gel.
Penam (III) and/or cepham (IV) may be converted to
cephcm (V) by treatment with base, as shown in the general
reaction scheme, above. Alternatively, if the cephem (V) is
the desired product, the penicillin sulfoxide (I) may be
reacted with the isocyanate (II) in the presence of a base
to give the cephem (V) directly. When preparing the cephem
directly in this manner, we have found that highest yields
of the cephem are obtained if a source of bromide ions is
also added to the reaction mixture.
When converting penam (III) and/or cepham (IV) to cephem
(V) by treatment with base, one may use any organic or
inorganic base. The reaction may be conducted in an organic
solvent by using a base which is soluble therein or by using
a two-phase aqueous-organic solvent system wherein the base is
water soluble.
-24-
~7C~3
When utilizing a two-phase system for base treat~ent
oE the penam and/or cepham, one may utilize any of the
ul3ual water-soluble bases, e.g. NaOH, KOH, K2C03, Na2C03,
NaHC03, XHC03, an alkaline phosphate buffer, or the like.
When the base treatment is conducted in an organic solvent,
one may use any of the usual organic-soluble bases, e.g. a
tertiary amine such as triethylamine, pyridine, quinoline,
isoquinoline, lutidine, tetramethylguanidine, or the li~e.
We have found that some bases such as X2C03, which are
generally considered to be insoluble in organic solvents,
appear to have sufficient solubility in certain organic
solvents such as dioxane to be utilized in such systems.
Thus, the penam ~III) and/or cepham (rV) ~either as
isolated products or as the crude reaction mixture) may be
con~erted to the corresponding cephe.~ (V) by adjusting a
solution the_eof to an al~aline p~ and maintaining it at
a~ al~aline pH for from about 15 minutes to 24 hours, depending
o~ the temperature, base, particular reactants and solvent
system. The tcmperature is not critical. We find that
0-40 is a convenient range and that 0-25 is preferred.
Higher temperatures may be used but normally decrease the
yield of desired product, while lower temperatures require
excessively long reaction times.
The base utilized to convert the penam and/or cepham
to the cephem need not be added in a stoichiometric amount,
as this is merely a catalyst. We have utilized from about
5 to about 150 mole percent of base and prefer to use from
about 20 to about 50 mole percent. A greater amount of base
may be utilized b~t normally does not increase the yield.
-25--
~5~ 3
The use of less than about 5 mole percent of base usually
unduly increaRe~ the reaction time and/or yield of product.
The most suitable amount of base depends on the particular
penam and/or cPpham being treated, as well as on the
particular solvent system.
As indicatsd above, we have found that, in the "one-
step" reaction of a penicillin sulfoxide with an isocyanate
in the presence of a ~ase to produce the cephem directly,
the yield of cephem is normally significa~tly increased by
the addition of a source of bromide ions to the reaction
mixture. Suitable sources of bromide ion will be apparent
to those skilled in the art, and include acetyl bromide,
propionyl bromidQ, benzoyl bromide, pyridine hydrobromide,
trimethylbromosilane, thionyl bromide, boron
tribromide, silicon tetrabromide, aluminum
tribromide, tin tetrabromide, and the like. The amount of
br ide giving the best yield of cephem will depend on the
particular penicillin sulfoxide, isocyanate, base and solvent
being utilized. We have found that from about 5 to about 50
mole percent of bromide is adequate while from about 10 to
about 30 mole percent is usually preferred.
After reaction of the penicillin sulfoxide with the
isocyanate to produce the desired penam (III), cepham (IV)
or cephem (V), the latter products will still contain a
protected carboxyl group, i.e. R7 is initially the same as
R4. It is usually desired ~o remove the protecting group
to pr~oduce the corresponding compound containing a free
carboxyl group (i.e. R7 is hydrogen). Removal of the carboxyl-
-26-
~7C~3
protecting group is achieved by conventional treatment,
e.g. catalytic hydrogenolysis in the case of the p-nitro-
benzyl protecting group. This may be accomplished, for
example, by the use of hydrogen in the presence of a catalyst
such as palladium or rhodium on a carrier such as char~oal,
barium sulfate or alumina. Alternative methods of removal
of the protecting group include reaction with Lewis acids
such as trifluoroacetic acid, formic acid or zinc bromide
in benzene (the reaction with Lewis acids may be facilitated
by the addition of a nucleophile such as anisole), or by
reduction with agents such as zinc/acetic acid or zinc~formic
acid, or by reaction with nucleophiles such as those containing
a nucleophilic oxygen or sulfur atom, e.g. alcohols, mercaptans
or water.
The side chains of penam (III), cepham (IV) and cephem (V)
may, if desired, be clea~ed to give the free 6-amino compound
(penam~) or 7-amino compound (cephams and cephems)~ Cleavage
may be e~fected by means of enzymes or by chemical hydrolysi~
or hydrogenolysis. If the side chain is to be cleaved, such
cleavage preferably is conducted prior to removal of the carboxyl-
protecting group. In the chemical hydrolysis of the sidechain, the penam, cepham or cephem is first converted to an
imino halide by reaction with a halogenating agent such as
phosphorus pentachloride, phosphorus oxychloride, phosgene,
thionyl chloride, oxalyl chloride or p-toluenesulfonyl
chlorid2 (and preferably phosphorus pentachloride or
phosphorus oxychloride) in the pre~ence of an acid binding
` agent. The reaction is conducted in an inert organic solvent
such as diethyl ether, nitromethane or a halogenated hydrocarbon
-27--
'
~ ~ ~7a~3
~methylene chloride and chloroform are the preferxed solvents).
It is preferred to use an excess of the halogenating agent
(up to about 2 moles per mole of penam, cepham or cephem)
and to use from about 1.5 to about 5 moles of acid binding
agent per mole of halogenating agent. Suitable acid binding
agents are tertiary amines such as triethylamine, N,N-dimethyl-
aniline, pyridine, quinoline lutidine, picoline and the like.
The reaction may be conducted at a temperature of from about
-60 to -10 for penams and at from about -60 to about +10
for cephams and cephems. We prefer to conduct the reaction
at from about -30 to about -40.
The imino halide prepared in the above step is then
converted into an imino ether by reaction with a primary or
secondary alcohol in the presence of an acid binding agent
(this is usually most simply accomplished by conducting
this step without isolation of the imino halide). Suitable
alcohols include alkanols such as methanol, ethanol, propanol,
isopropanol, butanol and isobutanol; aralXanols such as benzyl
alcohol and 2-phenylethanol; cycloalkanols such as cyclohexanol;
and alkanedisls such as ethylene glycol and l,6-hexanediol.
The preferred alcohol is methanol. The reaction may be
conducted over the same temperature range as in the formation
of the imino halide, and preferably is conducted at from about
-30 to about -40.
The imino ether is then hydrolyzed to produce the free
amino compound. This is most simply accomplished by quenching
the solution of the imino ether with watex at a temperature
of from about -5 to about +10.
-28-
7~3~3
Chemical cleavage of the acyl side-chain, such as
described above, alRo will remove some or all of the
substituent R on the penam and cepham, depending on the
particular nature of R6, the particular halo~enating agent
which i8 utilized, the temperature at which the reaction is
conducted, the particular work-up procedure, etc.. Thus,
with the penam having a phenoxyacetamido side-chain and R6
substituent which ~s trichloroacetyl, PC15 mediated cleavage
followed by wor~ up in methanol with a bicar~onate will
remove both groups. In such cases (where two acyl groups
are being removed~ one should utilize about twice the
amount of halogenating agent and alcohol referred to above.
In those cases where little or no R6 group is removed during
Ride-chain cleavage, the æmount o~ halogenating agent and
alcohol should be in the range stated above. It will be
appreciated by those skilled in the art that PC15 side-chain
cleavage cannot be utilized on compounds III or rv wherein
R6 is hydrogen, since the free carbamoyl group will be
destroyed. The side-chain may be removed without r~moving
substituent R6 of the penam or cepham (wherein R6 is other
than hydrogen) by utilizing specific halogenating agent~
and specific R6 substituents. Similarly, one may ramove
the R6 substituent of the penam or cepham without removing
the side-chain by utilizing suitable R6 substituents and
methods of removal, eOg. if R6 is chloroacetyl, it may be
removed with thiourea, without removing the side-chain.
The trichloroacetyl group may be removed by the use of
sodi~m bicarbonate in methanol.
Cleavage of the 6- or 7-acyl side-chain in the penam
~III) or cepham (IV~ may be achieved by hydrogenolysis
techniques when the side-chain ic a group readily removed
~y such techniques, e.g. p-nitrobenzyloxycarbonvl~
-29-
ii7~3~3
When a penicillin sulfoxide ester of Formula I isreacted with an isocyanate of Formula II in which n = 1
(i.e. a monoisocyanate), R6 in the resulting penam (III) or
cepham (n) will be the same as R5. If, however, n is
greater than 1 (i.e. is 2-4), then the resulting R6
substituent on the penam or cepham may have the structure
XII shown above. Thus, if a penicillin sulfoxide e~ter is
reacted with, for example, carbonyl diisocyanate, the
initially resulting prcduct will be a carbonyl group which
is substituted with two penam moieties, with two cepham
moieties, or with one penam moiety and 1 cepham moiety,
or a mixture of these products. Such bis , tris- and tetrakis-
penam or cepham compounds may be utilized in that form ~after
removal o~ the carboxyl protecting groups) or they may be
split to the mono-substituted compounds either under normal
workup .steps or by subsequent procedures.
After cleavage of the side-chains from the penam (III),
cepham (IV) or cephem (V) to produce the free amino compounds
of Formula VI~ ~II or VIII, the latter compounds may be
reacylated with a different side-chain to produce compounds
of Formula IX, X or XI. Briefly, a compound of Formula
VI, VII or VIII is reacted with an acid of the formula
o
R8-COH XIII
or with an acylating derivative of said acid, in which
o
R8-~- is a conventional acyl group known in the psnicillin or
cephalosporin art. Such conventional acyl groups include,
but are not limited to, those e~emplified above for R2.
-30-
~ ~7C~3
In the acylation of a compound of Foxmula VI, VII or
VII;I, the carboxylic acid of formula XIII may be used
se in which case it is preferred to use an enzyme or a
condensing agent. Suitable condensing agents include, N,N-
dimethylchloroform~minium chloride, an N,N'-carbonyldiimida-
zole or an N,N'-carbonylditriazole, a carbodiimide reagent
~especially N,N'-dicyclohexylcarbodiimide, N,N'-diisopropyl-
carbodiimide or N-cyclohexyl-N'-(2-morpholinoethyl)carbodiimide~,
a~ alkynylamine rçagent, i~oxazolium salt reagent, ~etenimine
reagent, hexachlorocyclotriphosphatriazine or hexabromocyclo-
triphosphatriazine, diphenylphosphoryl azide (DPPA), diethyl-
phoaphosphorylcyanide (DEPC), diphenylphosphite or rl-eth
carbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ).
As an alternative to using the carboxylic acid XIII
in the above process, there may also be employed reactive
acylating derivatives of acid XIII, i.e. functional equivalents
of the acid as acylating agents for a primary amino group.
Examples of reactive acylating derivatives of the carboxylic
acid include the acid halide (e.g. acid chloride or acid
bromide), acid anhydrides, including mixed anhydrides (e.g.
alkoxyformic anhydrides), acid azides, active esters (e.g.
p-nitrophenyl) and active thioesters. Another reactive deri-
vative of the acid is a corresponding azolide, i.e. an amide
of the acid whose amide nitrogen is a member of a quasiaromatic
five-membered ring containing at le~st tw-o nitrogen atoms,
i.e. imidazole, pyrazole, the triazoles, benzimidazole,
benzotriazole and their substituted derivatives. The general
method for preparation of azolides is described, for example~
in U. S. Patent 3,910,900.
~ ~7~ 3
Mention was made above of the use of enzymes to
couple the free acid with a compound of Formula VI, VII or
VIII. Included in the scope of such processes are the use
of an ester, e.g. the methyl ester, of that free acid with
enzymes provided by various microorganisms, e.g. those
described in J Am. Chem. Soc., 94(11), 4035-4037 ~1972),
J Antibiotics (Japan), 24(S), 321-323 (1971) and U. S.
Patent 3,682,777.
The acylation process is conducted in a reaction-inert
solvent system which can be aqueous or non-aqueous. Suitable
reaction-inert solvents include, for example, water, acetone,
tetrahydrofuran, dioxane, acetonitrile, dimethylformamide,
dimethylsul~oxide, methylene chloride, chloroform, benzene,
toluene, methyl isobutyl ketone and mixtures of the above-
mentioned organic solvents with water. The choice of solvent,
i.e. particularly whether an aqueous or non-aqueous solvent
is used, is dependent on the particular starting materials
employed. Thus, for example, if the starting compound of
Formula VI, VII or VIII is used in the form where the 3- or
4- carboxyl moiety is protected by an ester group cleaved by
hydroxylic solvents, e.g. a silyl or stannyl ester, an aprotic
organic solvent is most preferably employed. When the
starting compound of Formula VI, VII or VIII is used in its
salt form, water or an aqueous organic solvent system is
preferably employed. The most advantageous solvent system
for the particular reagents used can be determined by routine
exper~entation.
-32-
i7~13
The duration and temperature of the acylation
rea,ction are not critical. Temperatures in the range of
frc~ about -30C to about +50C are commonly used for
reaction times ranging from less than one hour up to a day
or more. Although the initial contacting of the reactants
is preerably carried out at around 0C to reduce the
incident of by-products, it is frequently desirable after
a few minutes of mixing to allow the reaction mixture to
warm to room temperature until the reaction is complete.
Any of compounds III-XI of this invention, after
rem~val of the carboxyl-protecting group R7, may be
converted, if desired, to a pharmaceutically acceptable
salt or to a physiologically hydrolyzed ester 3uch as the
pivaloyloxymethyl, acetoxymethyl, phthalidyl, 5-indanyl or
methoxymethyl ester.
A~ shown by the wavy lines in the structural formula
for Compound I, the substituents on the 6-position may have
either stereochemical configuration, i.e. the amino moiety
may have the normal ~ configuration and ~3 the normal a
configuration, or these may be reversed. Whatever the
configuration at the 6-position of starting Compound I, the
same configuration will be maintained in the penam, cepham
or cephem product.
~ owever, the configuration of the 2-position of
penam III or the 3-position of cepham rv is dependent on the
configuration of the sulfoxi~e moiety of starting Compound I.
Thus, as shown in the following equations, the S sulfoxide
-33-
i7~3i3
(Ia) gives pr~marily the R penam (IIIa) or S cepham (IVa),
whi.le the R sulfoxide (Ib) gives primarily the S penam
(IIIb) or the R cepham (IVb)~ which readily elLminates to
thle cephem.
R2/ ~ CRCR3 + R NCO >
C09R
(Ia)
[S-sulfoxide]
R1 R3 S CH20CNHR R \ R3 S
R2~ ~ ~ COOR ~ CH3
COOR
(IIIa)
[R penam] (Iva)
R2 / ~ 3 ~ R5NCo >
COOR
(Ib)
lR sulfoxide]
-34-
~ ~7 ~1 3
R2/ ~ 4nd R ~ CCU~R6
COOR
(IIIb) ~IYb)
[S penaml tR cepham]
Depending on the particular substituent groups on the starting
penicillin sulfoxide, small to moderate amounts of the product
having the alternate configuration may also be prsduced.
The reaction of penicillin sulfoxides of Formula I
with i~ocyanates of Formula II to produce the penams of
Formula III and/or the ring-expanded cephams and cephems of
Formulae IV and V, respectively, is completely unprecedented.
The literature indicates that sulfoxides react with activated
is.ocyanates such as acyl isocyanates to produce sulfilimines.
The literature also indicates that activated isocyanates
such as acyl isocyanates react with amides to give acyl ureaq and
amidines (see, for example, H. Ulrich, Chemical Reviews,
65, 369 (19~5)). It would therefore be expected that
penicillin sulfoxides would give such unwanted products upon
reaction with activated isocyanates such as those described
herein, particularly at elevated temperatures. To our surprise,
we have found that acyl isocyanates and other activated
isocyanates of Formula II, above, react with penicillin
sulfoxides (in which the carboxyl group is bloc~ed) to give
the new 2-carbamoyloxymethylpenams of Formula III and 3-
-35-
~57~3
carbamoyloxycephams of Formula IV, as well as the corr~-
sponding 3-methyl-~3-cephems of Formula V.
In terms of the ring-expansion aspect of the present
invention, the use of isocyanates of Formula II offer several
advantages over presently known ring expansion processes,
e.g..
1) Isocyanates of Formula II maintain an anhydrous
situation throughout the ring expansion reaction, thus
avoiding the water-induced degradation reactions which can
occur in catalytic ring expansion processes.
2) Ring expansion utilizing isocyanates of Formula
II are faster than catalytic ring expansion processes.
3) I~ocyanates of Formula II are twice as effective
in scavenging active hydrogen compounds than the trimethyl-
silyl compound~ used in some other processes. Thus, o~e
molecule of water is scavenged by one isocyanate group or
by two trimethylsilyl groups.
4) Isocyanates such as acetyl isocyanate, methane-
sulfonyl isocyanate, sulfonyl diisocyanate, carbonyl diisocyanate
and phosphorous triisocyanate give, as reaction by-products,
acetamide + C02, methanesulfonamide + C02, sulfonæmide + C02,
urea + C02 and phosphorous amides ~ C02, respectively. These
are simpler to handle and dispose of than by-products from
processes utilizing bistrimethylsilyl urea, i.e. urea +
hexamethyldisiloxane. Further, such neutral amide by-products
do not react with the lactam ring.
-36-
~5~ 3
5) ~any of the isocyanates of Formula II are
substantially less expensive than bistrimethylsilyl urea
ancl other trimethylsilyl ureas utilized in other ring
expansion processes.
6) Many of the isocyanates of Formula II are
liquids at room temperature. From a practical plant
point of view, liquids are easier, and generally safer
and less costly to dispense and handle than solids.
Most of the silyl compounds utilized in other ring-expansion
processes are solids.
7) From a practical point of view, isocyanates of
Formula II may be ~elected such that their by-products are
ea~ily qeparated from the desired product by dif~erent
techniques. For example, acyl isocyanates give water-soluble
amides as by-products. Silicon tetraisocyanate, on the other
hand, gives silica as a by-product, which is completely
insoluble in either organic or aqueous solvents.
The starting compounds for use in the present process
are either known (many are commercially available) or may be
prepared by known procedures from readily available materials.
~any of the penicillin sulfoxides of Formula I are known;
others may be prepared from the corresponding penicillin
by standard techniques well known to those s~illed in the art,
e.g. by use of sodium metaperiodate, hydrogen peroxide in
acetic acid, m-chloroperbenzoic acid, iodobenzene dichloride
in aqueous pyridine, ozone, or aqueous bromine. The penicillins
themselves also are either known or may be prepared by acylating
6-aminopenicillanic acid with the appropriate side-chain acid,
using standard procedures known in the art.
~ ~7~ 3
The isocyanate~ of Formula II also are known or are
realdily prepared by known techniques from available starting
materials. Thus, acetyl i~ocyanate and ~imilar isocyanates
may be prepared by the procedure de~cxibed in Berichte, 36,
3213 (1903); the preparation of chloroacetyl i~ocyanate i~
described in J. Org. Chem., 27, 3742 (1962); the preparation
of 3ilicon tetraiRocyanate is described in Inorganic
Syntheses, 8, 27 (1966); the preparation of sulfonyl dii~o-
cyanate iR described in W. German Pa~ents 940,351 and 1,150,093,
and the preparation of methylsulfonyl isocyanate is described
in J. Org. Chem., 39, 1597 (1974). General procedures for the
preparation of many sulfonyl $~ocyanates are given in Chemical
Reviews, 65, 369 (1965) and references cited therein.
The penams of Pormulae III and IX, the cephams of
Formulae rv and X, and the cephems of Formulae V and XI
provided by the pre~ent invention ~after removal of the
carboxyl-protecting group to produce the free acid) are
active against various Gram-po~itive and Gram-negative
organi~ms and, accordingly, are useful anti~acterial
agents for the treatment of diseases caused by such
organi~ms in animals, including man.
The free-amino compounds of Formulae VI, VII and
VIII obtained by side-chain cleavage of the compounds of
Formulae III, IV and V, respectively, generally have lower
antibacterial activity than compounds III-rV or IX-XI.
Although they may sometimes ~e utilized therapeutically,
their primary utility i8 as intermediates in the preparation
of compounds of Formulae IX-XI by re-acylation of the free
amino group.
-38-
~5~ 13
The an~ibacterial compounds provided ~y the present
invention may be used alone or as the (or an) active ingredient
in a conventional pharmaceutical composition, by analogy
with other penicillins and cephalosporins. They may be
adminîstered orally, parenterally or by suppository. For
oral administration the co~positions may be in the form of
tablets, capsules, powders, granules, lozenges, solutions
or suspensions. They may contain conventional excipients
suitable to the dosaye form, e.g. binding agents, fillers,
lubricants, disintegrating agents, wetting agents, stabilizers,
sweetening agents, flavors, and the like. Suppo~itories
will contain conventional suppository bases. For parenteral
administration, one may utilize fluid unit dosage forms such
as ~te~ile solutions or suspensions, or sterile powders
intended for reconstitution with a sterile vehicle prior to
administration. Conventional adju~ants such as preservatives,
buffering agents, suspending agents, and the like may be
included in parenteral compositions.
The compositions may contain from 0.1% to 99% by
weight of the antibacterial compounds of the present invention.
When the compositions are in unit dosage form, each unit will
contain from about 100-750 mg of the active ingredient.
They are administered in an amount of from about 15 to about
250 mg/kg/day in divided doses, e.g. 3 to 4 times per day.
It will be appreciated by those skilled in the art
that the penams ~III and IXJ, cephams (rV and X~ and cephems
(V and XI~ pro~ided ~y the present invention potential}y
contain an asymmetric carbon atom in their side-chain.
It is specifically intended that this invention include all
possible epimers, as well as mixtures thereof.
-39-
7~3
The Minimum Inhibitory Concentrations (MICIs) of some
of the compounds of thig invention were detexmined against
a number of organisms, and the results are shown in Table 1.
The substituents ~R" and "X~ in Table 1 ref er to the stated
substituents on the following skeletal struc~ure
S~
~J~
COO~
This inventlon is illustrated by, but in no way
limited to, the specific Examples.
-40-
~L~57~13
~ -- ~ ~ ~1 ~ ~
~ E . o . _
a ~ ~ o ~ O co
, ~U j~
~-c,
~ ~ ~ o C
~, ~ ~ _ _
E ," o o
. ~~ o o o
i ~7~ I ~
=~ a~
1~ ~ ~ ~ ~
/ O ~ ~D / \ ~y / \
/ ~ ~ ll ll ll ll
/ _ . ~ X ~ X X
--41--
7~
_ _ _ _ I
_ _
. _
.
Q~ l
O O In
.~ ~ J~
~ ~ ~ x ~ ~ ,
--42--
~57(~3
¦ N ~
_ _
_ .
I _ _
~ ` ~
-43-
~7~3
~ A U~
~ _
E~ ~r _l _~
i~;
X ~ X X X
_ . _ _ ,
~7~3
Ex~mpl~ 1
A) (2R,3S,5R,6R) 2-(U-Acetvl)car~amoYloxvmethvl-2-
methYl-6-phenoxyacetamidopenam-3-carboxvlic
Acid -Nitrobenz 1 Ester
P Y
A solution of (lS,3S,5R,6R) 2,2-dLmethyl-6-phenoxy-
acetamidopenam-3-car~oxylic acid-l-oxide p-nitrobenzyl ester
(25.18 g, 50.0 mmol), acetyl isocyanate (8.50 ml, 9.53 g,
112 mmol), and dioxane (250 ml) was refluxed under ~itrogen
for 5 hours, cooled and concentrated in vacuo to a yellow
foam. The foam was chromato.graphed on silica gel (1.7 Kg)
with methylene chloride: acetone; 9:1; v:v to give four
products; the 3-methyl-~3-cephem; starting sulfoxlde, the
title penam, and the cepham (in order of elution). The
penam fractions were concentrated to a colorless foam in
40.2~ yield (11.80 g). Re-chromatography of a portion gave
n analytical sample. m.p. 83-85; nmr 100 MHz (C~C13) ppm
O O
Il il
8.40 tl,3, CNHC),- 8.20 (2, d, J = 8.5, 1/2 aromatic AB pNB),
7.56 (3, d, J = 8.5 over m, 1/2 AB, pNB and C6-NH), 7.5 (2, m)
and 6.9 (3, m, O-Ph-H's), 5.7 (2, m's, C5-C6-H's), 5.32
(2, br s, pNB methylene), 4.88 (1, s, C3-H), 4.56 (2, s,
OC~2C), 4.26 and 4.06 ~2, d's,J S 11.5, AB of C2-CH2O), 2.22
(3, s, C-CH3), and 1.47 (3, ~, C2-C~3); nmr 13C 4 carbonyls
ca 170 ppm, carbamate carbonyl C 157.0, C~ singlet at 67.4,
while C2-C~2O is t At 72.3, and C2-CH3 is q at 21~7.
Anal- Calc'd for C26H26N4l0S: C, 53.23; H, 4.47; N, 9.55.
Found: C, 53.21; H, 4.49; N, 9.39.
-45-
~57~3
B) (3S,4R,5R,6R) 3-tN-acetYl)carbamoyloxy-3-
methyl-7-~henoxy~cetamidocepham-4-
carboxylic acid p-nitrobenz~l ester
The final chromatographic band from Step A, above,
was concentrated in vacuo to give the title cepham in
12.4% yield (3.66 g): nmr (CDC13) 100 MHz ppm 9.89 (1, s,
O O
CNHC), 8.23 (2, d, J - a.2 Hz, 1/2 p-NB AB), 7.56 (2, d, J =
8.2, 1/2 pNB AB) 7.24 (2, m) and 6.9 (3, m, OPh-H's), 5.55
(1, dd, J = 9.5, 4.0, C7-H), 5.32 ~3, br 9 over m, pNB-CH2
and C6-H), 4.94 (1, s, C4-H), 4.52 (2, 8, OC~2C)~ 3.56 and
3.34 (2, 2 d'~, J 3 15.5, C2-H2 AB), 2.27 (3, 9, C-C~3), and
1.60 ~3, s, C4-C~3); 13C 4 carbonyls ca 170 ppm carbamate
carbonyl C 157.0, C2 (t, 29.5), C3 (s, 74.3), C4-CH3 ~q, 21.7).
Exa~le 2
(2R,3S,5R,6R) 2-(N-Acetyl)carbamoyloxvmethyl-2-
methyl-6-phenoxv~cetamidopenam-3-car~oxylic Acid
A suspension of 10~ palladium on charcoal (400 mg) in
sthyl acetate ~40 ml) and aqueous 0.5% sodium bicarbonate
was prehydrogenated and charged with t2~,3S,5R,6R) 2-(N-
acetyl)carbamoyloxymethyl-2-methyl-6-phenoxyacetamidopenam-
3-carboxylic acid p-nitrobenzyl ester (400 mg 0.68 mmol).
The whole was shaken at 50 psi hydrogen pressure for 30
minutes and polish filtered. The aqueous was washed with
ethyl acetate ~20 ml), combined with a back extract of H20
-46-
~ ~ ~;7~l 3
(20 ml), overlayed with ethyl acetate (25 ml) and adjusted
to pH 2.9 with 35% sulfuric acid. The layers were separated
and the rich organic phase was washed with water (20 ml),
combined with a back extract (EtOAc, 20 ml), dried (4A
sieves)~ polish filtered and concentrated in vacuo to a
colorless foam (270 mg) in 87% yield: nmr 100 MHz (CDC13-D20)
ppm 7.32 (2, m, m-phenyl ~'s3 6.96 (3, m, o,p-phenyl H7s),
5.59 (2, br s, mag equiv. C5,C6-~'s), 4.79 (l, s, C3-H),
4.59 (HOD and OC~2C~, 4.08 (m, AB of C2-CH2O), 2.25 (3, s,
CC~3), and 1.58 (3, s, C3-Me) with small ethyl acetate impurlty.
Ex~m~le 3
(2R,3S,5R,6R) p-Nitro~enzvl 2-(N-Chloroacetvl)-
carbamo~loxymethvl-2-methvl-6-
(2-phenoxyacetamido)penam-3-carboxYlate
A solution of (lS,3S,5R,6R) 2,2-dimethyl-6-phenoxy-
acetamidopenam-3-carboxylic acid-l-oxide p-nitrobenzyl
ester (5.01 g, 10.0 mmol) and chloroacetyl isocyanate (5~0
g, 40 mmol) in dioxane (50 ml) was heated at reflux under
nitrogen for 4 hours. The solution was concentrated in
vacuo and crudely separated ~y filtration through silica
gel (75 g) with methylene chloride:acetone (9:1, v/v).
The filtrate was concentrated and chromatographed on silica
gel (140 g) with the same solvent. The second of three
product bands (cephem, penam, and cepham) was concentrated
in vacuo to crude product (0.53 g) a portion of which (0.23 g)
-~7-
~5~3
was crystallized ~rom hot methanol (5 ml, Darco) to return
the title compound as a colorless ~olid (0.11 q): nmr (CDC13,
O O
Il 11
100 MHz) ppm 8.46 (br s, 1, -CN~C-), 8.21 (d, 2, J = 13.2 Hz,
l/2 aromatic AB p-~02benzyl), 7.4 ~overlapping m's, 5, lJ2
AB, acyl NH, and orthophenoxy), 6.95 (mls, 3, m,p-phenoxyl),
5.7 (overlapping m's, 2, C5,C6-H's), 5.30 (s, 2, benzyl-CH2),
4.81 (s, l, C3-H), 4.54 (s, 2, phenoxyacetyl CH2); 4.25 (o~er-
lapping AB m's, 4, ClCH2 and C2-C~2O), and 1.45 (s, 3, CH3);
13C nmr consistent with four carbonyls ca 170 ppm and car~amate
carbonyl at 157.2 ppm.
E~a~E~:_ 4
A) (2R,3S,5R,6R)2-Carbamoyloxvmethyl-2-methyl-6-
(2-ethoxynaphthoylamido)penam-3-carboxylic
Acid p-Nitrobenz~l Ester
A solution of trichloroacetyl isocyanate (4.2 ml, 6.6
g, 35 mmol), (lS,3S,SR,6R) 2,2-dimethyl-6-(2-ethoxynaphthoyl-
amido)penam-3-carboxylic acid-l-oxide p-nitrobenzyl ester
(7.35 g, 12.5 mmol), and dioxane (65 ml) was refluxed under
nitrogen for 3.5 hours and concentrated in vacuo to an oil.
The oil was taken into methanol (125 ml)~ the solution was
adjusted to pH 7.4 with 5% sodium bicar~onate, and the
mixture was held at pH 7.4 to 7.5 with 3% H2SO4 for 2 hours.
A precipitate was removed by filtration with a methanol wash
(20 ml), and the filtrate was distributed between methylene
-48-
~57~L3
chloride (250 ml) and water (80 ml). The organic lay~r was
washed with water ~75 ml), combined with a back-extract
~CHC12, 75 ml~, dried (4A sieve), polish filtered, and
concentrated in vacuo.
The concentrate was chromatographed on silica gel
(500 g) with CX2C12:acetone, 9:1, v:v to give three major
products; the ~3 cephem, the title penam, and the cepham
(see below). The middle fractions were concentrated to a
very pale yellow foam ~1.49 g) 19.6%:
nmr 100 MHz ~5DC13) ppm 8.41 (2, d, J = 9 Hz, 1/2
arGmatic AB pNB), 8.0-7.1 ~9, aromatics +NH), 6~08 (1, dd,
J ~ 4.2, 9, C6-~1), 5.74 (1, d, J - 4.2, CS-H), 5.36 and 5.21
(2, d's, J ~ 13, A3 pNB methylene), 4.73 ~ , C3-1I), 4.60
(2, br s, NH2), 4.21 ~q, J = 7) with 4.12 ~d, J ~ 11.5, total
3, OC~2C~3 and C2-CH~0-), 3.84 ~1, d, J = 11.5, C2-CHHO),
and 1.40 ~t, J = 7) with 1.38 ~g, total 6, CH2CH3 and C2-
CH3)-
B) ~3S,4~,5R,6R)-3-Car~amovloxy-3-methyl-7-
1 2-etho~y~thoylamido ) ceæham-4 -
carboxylic Acid p-Nitrobenz~l Ester
The last major product fractions of Step A, a~ove, were
concentrated in vac~o to give the title product as a light
yellow foam (2.Ç~, 0.20 g); nmr CDC13 80 M~z ppm 8.5-6.9
(7, m's, aromatics and C7-NH), 5.96 (1, dd, J = 9.3, 4.5 Hz,
C7-H), 5.44 ~1, d, J = 4.5, C6-H), 4.21 ~2, s, pNB C~2), 4.87
_,~g_
(1, g, C4-H), 4.71 (2, br s, -NH2), 4.24 (2, q, J = 7.0, CH2-
CH3), 3.54 (1, br d, J - 14.6, 1/2 C2AB), 3.28 (1, d, J = 1~.6,
1/2 C2 AB), and 1.48 (s, C3-CH3) with 1.44 (t, J = 7.0, total
6).
Example 5
(2R,3S,SR,6~) 2-CarbamoYloxymethyl-2-methyl-6
(2-ethoxvnaphthoYlamido)penam-3-carboxYlic Acid
The p-nitrobenzyl ester of the title compound t610 mg,
1.0 mmol) was added to a prehydrogenated suspension of 10
palladium on carbon in ethyl acetate (25 ml) and aqueous
potassium bicarbonate (0.4%, 20 ml). The whole was shaken
at 50 psi hydrogen pressure for 60 minutes, and cen~rifuged.
The organic phase and the solids were extracted with 0.2%
KHCO3 (2 x 20 ml) and the combined aqueous phase was washed
with methylene chloride (20 ml). The aqueous phase was
stirred with fresh CH2C12 (25 ml) during pH adjustment to
2.0 with 35% sulfuric acid and the layers were separated.
The rich organic phase was washed with pN 2 buffer (lS ml),
combined with a back extract (CH2C12, 25 ml), dried (4A sieves),
polish filtered, and concentrated in vacuo to a green-tinted
foam (170 mg) 36%: nmr 100 MHz (CDC13) ppm 8.1-7.1 (8, 3 m's
aromatics + C6-~H, exchangeable near 7.9), 5.98 (1, dd, J = 4,
--~0--
5~
8 5 Hz, C6-H), 5.75 ~1, d, J = 4, C5-}I), 5.54 (2, ~r s,
exchangeable, NH2), 4.62 (1, s, C3-H), 4.23 ~q, J = 7) and
4.19 ~d, J ~ 5, 3 total, OCH2C~3 and 1/2 CXHO AB), 3.86
tl, d, J = 11.5, 1/2 C~HO), and 1.57 (s) with 1.44 ~t, J = 7,
total 6~ C2-C~3 and cH2-cH3).
Exam~le 6
(2R,3S,5R,6R) 2-Carbamo~loxYmethyl-2-methyl-6-
(2-phenoxyacetamido)penam-3-carboxylic
Acid -Nitrobenz 1 Ester
P ~
A ~olution of (lS,3S,5R,6R) 2,2-dimethyL-6-phenoxy-
acetamidopenam-3-carboxylic acid-l-oxide p-nitrobenzyl ester
(7.52 g, 15.0 mmol) and trichloroacetyl isocyanate (5.0 ml,
7.9 g, 42 mmol) in dioxane (75 ml) was refluxed under nitrogen
for 3.5 hours and conc ntrated in vacuo. The concentrate
was 3tirred with methanol (100 ml) and the solution was
decanted frcm a black tar with methanol rinses ~2 x 10 ml).
The æolution was diluted with water (5 ml), adjusted to plI
7.4 with 5% sodium bicarbonate, and held at pH 7.4-7.5 with
3% H2S04 for 2.5 hours. The mixture was distributed between
methylene chloride (100 ml) and water (50 ml). The organic
phase was washed with water (50 ml), combined with a CH2C12
bac~ extract (50 ml), dried (4A molecular sieve~, polish
filterecl with CH2C12 washes (2 x 20 ml), and c:oncentrated
in vacuo to a light brown oil.
-
-51-
~57~3
The oil was chromatographed on silica gel ( 500 g ) with
methylene chloride:acetone, (9:1 v:v) to give the title
prc~uct, as the second of two major zones, concentrated in
vacuo to a pale yellow ~oam (2.01 g) 25%; identical by nmr
and tlc to the analytical sample prepared by a second
chromatography and concentration to a colorless foam: mp
76^d; n~r (CDC13) 100 M~z ppm 8.22 (2, d, J = 9 Hz, 1/2
aromatic AB pNB), 7.52 overlapping 6.8-7.7 (8, d, J = 9
1/2 pNB, with m's phenoxy ~1's, NH), 5.75 (dd, J = 4, 9
C6-~I) with 5.63 (d, J = 4, total 2, C5-~), 5.37 and 5.22
(2, 2 d's J - 13.5, AB pNB methylene), 4.73 (1, s, C3-H),
4.55 (2, s, -OCH2C-), 4.16 and 4.00 (2, 2 d's J - 11.5,
AB C2-CH2-0), and 1.41 (3, g C2-C~3).
Anal. Calc~d for C24H24N4O9S: C, 52-93; ~, 4-44; ~, 10-29;
s, 5.89
Found: C, S2.82; H, 4.51; N, 10.11;
s, 5.78
Example 7
(2R,3SL5R,6R) 2-Carbamo~loxvmethvl-2-methvl-6-
phenoxvacetamidope ~ xYlic Acid
The p-nitrobenzyl es~er of the title compound (1.09 g
2.0 mmol) was added to a prehydrogenated suspension of
10% palladium on charcoal (0.55 g) in ethyl acetate (50 ml)
and 0.4% aqueous potassium bicarbonate (35 ml). The whole
was shaken at 50 psi hydrogen pressure for 1.4 hours and
-52-
~57~3
fi.ltered, with 0.4% bicarbonate (2 x 3 ml) and water (5 ml)
wa~shes. The layera were separated and the agueous phase was
walshed with CHC13 (2U ml), combined with an H20 bac~ extract
~10 ml), and stirred with CH2C12 (25 ml) during p~ adjustment
to 2.0 with 35% sulfuric acid. The organic phase was
separated, washed with pH 2 buffer ~10 ml), dried over 4A
sieves, polish filtered a~d concentrated in vacuo to a color~
less foam (0.25 g) in 29% yield; nmr lQ0 MHz (CDC13-D20)
ppm 7.3 (2, m, meta-H's), 7.0 (3, m, o,p-~15), 5.7 ~2, m's,
O
C C -~'s), 4.74 (1, s, C3-~), 4.59 12, s, OC~2C),
4.04 ~1 ea, ABq, J - 11.5, C2-C~20), 1.58 (3, s, C2-C ~ ).
Ex~
~2R,3S,5R,6R) 2-~N-Acet~l)carbamoylox~methvl-
2-methyl-6-~3-(2,6-dichloro~hen~1)-5-
methYlisoxa2ol-4-ylamid ~ ~enam-3-
carboxylic Acid P-Nitrobenzyl Ester
I
A suspension of (lS,3S,5R,6R) 2,2-dimethyl-6-~3-
(2,6-dichlorophenyl)-5-methylisoxazol-4-ylamido]penam-3-
carboxylic acid-l-oxide p-nitrobenzyl ester (6.21 g, 10.0
mmol~ in dioxane ~50 ml) with acetyl isocyanate (2.3 ml, 30
mmol) was stirred at reflux under nitrogen for 6 hours.
The resulting clear solution was concentrated ln vacuo to
a light orange foam. Chromatography of this foam on silica
gel (500 g) with methylene chloride:acetone; 9:1; v:v gave
3 major fractions, the ~3 cephem, the title penam, and the
-53-
ceE~ham analog. The penam was obtained by concentration as
an off-white foam in 44% yield ~3.12 g): mp 85d; nmr ~CDC13)
100 MHz ppm 8.23 ~d, J - 8.5 Hz) overlapping 8.17 (s, 3 total,
O o
1/2 aromatic AB pNB and -CNHC-), 7.53 (d, J = 8.5) overlapping
7.48 (g, 5 total 1/2 pNB AB and other aromatics), 6.22 (1, d,
J - 9.5, C6-N~), 5.79 (1, dd, J = 4, 9.5, C6-H), 5.58 (1, d,
J = 4, C5-H), 5~39 and 5.21 ~2, 2 d's, J - 13, AB pNB methylene,
4.72 ~1, s, C3-H), 4.14 ~1, d, J = 11, C2-CHHO), 3.62 (1, d,
o
J = 11, C2-CHHO), 2.81 ~3, s, isox-CH3), 2.31 (3, s, CCH3),
and 1.39 (3, g, C2-C~3).
nal. Calc'd for C29H25N5OloSC12: C, 4g.30; H, 3.57; ~, 4.54;
Cl, 10.04.
Found: C, 49.31; H, 3.83; s, 4.30;
Cl, 10.17.
Exam~le 9
2R,35,5R,6R) 2-(N-AcetYl)carbamovloxYmethYl-
2-methyl-6-~henylacetamidoPenam-3
carboxylic Acid p-Nitrobenzyl Ester
A solution of (lS,3S,5R,6R) 2,2-dimethyl-6-phenyl-
acetamidopenam-3-carboxylic acid -l-oxide p-nitrobenzyl ester
(4.85 g, 10.0 mmol) and acetyl isocyanate (2.3 ml, 30 mmol)
in dioxane ~50 ml) was refluxed under nitroge~ for 7 hours.
-54-
~i7~3
The light orange solution was concentrated in va uo to a
foa~ which was chromatographed on silica gel (500 g) with
met:hylene chloride:acetone; 9:1, v:v. Two major bands were
eluted; the fir~t wa~ the ~3 3-methylcephem (28%, 1.29 g)
and the second was the title compound obtained in 45% yield
(2.56 g) as an off-white foam: mp 83-85; nmr 100 MHz (CDC13)
ppm 8.24 (2, d, J - 9 Hz, 1/2 aromatic AB pNB), 7.61 (2, d,
J = 9, 1/2 pNB AB), 7.28 (5, ~, phenyl), 5.54 (2, m's C6-C5-
H's), 5.40 (2, br s, pNB methylene), 4.91 (1, ~, C3-H), 4.27
1, d, J - 12, 1/2 C2-C~0 AB), 4 08 (1, d, J = 12, 1/2 C2-
methylene AB), 3.12 (2, s, PhC~2CN), 2.12 (3, s, acetyl), and1.41 (3, ~, C2-Ca3).
Anal. Calc'd. for C~6H26N409S: C, S4~73; H, 4.59; N, 9.82.
Found: C, 54.53; H, 4.79; N, 9.82.
~xam~le 10
(2~!35,5R,6R) 2-(N-Acetvl)carbamoYloxymethvl-2-
methvl-6-(5-methyl-3-phenyl-4-isoxazolyl)-
amidoPenam-3-carboxylic Acid ~-NitrobenzYl Ester
A suspension of (lS,3S,5R,6R) Z,2-dimethyl-6-(5-methyl-
3-phenyl-4-isoxazolyl)amidopenam-3-carboxylic acid-l-oxide
p-nitrobenzyl ester (5.53 g, 10.0 mmol) wa~ treated in
refluxing dioxane (50 ml) with acetyl isocyanate (2.3 ml,
30 mmol) for 6 hours. The unreacted ester (1.26 g, 2.3
mmol) was removed by filtration and the filtrate was concen-
~L~L57(~3
triated in vacuo to a dar~ yellow foam which was chromato-
-
graphed on silica gel (500 g) with methylene chloride:acetone~
~9:1; v:v). The product fraction was concentrated ln vacuo
to a colorless foam (1.02 g) in 20.5% yield; nmr 100 MHz
(CDC13) ppm 9,20 (2, d, J = 8.5 Hz, 1/2 pNB AB), 8.84
O O
(1, br 5, C~C) ~ 8.50 with 8.46 (7, m's, 1~2 pNB and phenyl
Hls), 8.23 (1, br d, J - 9, C6-NH), 5.76 (1, dd, J - 4, g,
C6-H), 5.51 (1, d, J = 4, C~ , 5,26 and 5.19 (2, ABq,
J = 13, pNB-C~2), 4.64 (1, s, C3-H), 4.03 (1, d, J = 11.5,
/ 2 -2-)~ 3-53 (1, d, J = ll.S, 1/2 AB C2-H20), 2.76
(3, s, oxazolyl-Me)~ 2.27 (3, s, CCH3) and 1.33 (3, s, C2-
CH3)-
~xample 11
A) (2R,3S,5R,6R) 2-(N-Acetvl)carbamoyloxYmethvl-2-
methyl-6-(2-ethoxynaphtho~lamido)penam-3-
carbo~ylic Acid p-N-trobenz~l Ester
A mixture of acetyl isocyanate t2.3 ml, 30 mmol),
lS,3S,SR,6R~ 2,2-dimethyl-6-(2-ethoxynaphthoylamido)penam-
3-car~oxylic acid-l-oxide p-nitrobenzyl ester (~.66 g, 10.0
mmol) and dioxane (50 ml) was refluxed ~or 6 hours and
concentrated in vacuo. The concentrate was chromatographed
on si~ica gel (500 g) with methylene chloride:acetone, 9:1,
v:v, Four major fractions were obtained; the ~3 3-methyl
cepham, the starting sulfoxide, the title penam, and the
-56-
~ ~5~3
cepham analog (in order of elution). The "penam~ fractions
were concentrated in vacuo to a pale yellow foam in 23% yield
(1.47 g): mp, 100 d; nmr (CDC13) 100 MHz ppm 8.29 ~2, d, J =
9 Hiz, 1/2 aromatic AB pNB), 8.0-7.1 (10, m's, aromatics +
NH's), 6.09 (1, dd, J - 9, 4, C6-~), 5.77 (1, d, J = 4, C5-H),
5.37 and 5.23 ~2, 2 d's, J - 13 Hz, AB pMB.methylene), 4.73
(1, s, C3-H), 4.32 (q, J = 7) over 4.29 (d, J a 11~ 3 total
CH2CH3 and 1/2 C2-CHHO), 3.91 (1, J - 11, C2-C~HO), 2.14 (3,
s, CCH33, and 1.42 (6, s ~ t, J = 7, C2-CH3 and CH2CH3).
C31H30N4olos C, 57.21; H, 4.65; N, 8 61;
S, 4.g3.
Founds C, 57.12; H, 4.72; N, 8.30;
S, 4.87.
B) (3S,4R,5R,6R)-3-(N-AcetYl)carbamoyloxy-3-methyl-7
(2-ethox~naphthovlamido)cephzm-4-
carboxYlic Acid p-Ni~robenzYl Ester
The final product fractions of Step A, above, yielded
the title co~pound as a pale yellow foam in 4.1% (0.27 g)
yield; nmr (CDC13) 100 MHz ppm 8.3-7.1 (11, m's aromatics
O O
and CNHC), 6.90 (1, br d, J - 8.5 Hz, C7-NH), 6.14 (1, dd,
J - 4.5, 8.5, C7-H), 5.35 (2, s, pNB C ~ ), 5.16 (1, d, J z
4.5, C6-H), 4.26 (2, q, J = 7, OC~2CH3), 3.60 (1, br d, J =
18, 1~2 AB C2-CH2), 3.22 (1, d, J = 18, 1/2 AB), 2.18 (3, s,
o
CCH3), and 1.58 (br s) with 1.49 (t, J = 7, total 6 protons,
C3-C~3 and C~2CH3).
-57-
~xam~le 12
(2~,3S,5R,6R) 2-C~ thyl-2-met~
6-t3-(2,6-dichlorophen~1)-5-methyl-4-isoxazolvl]-
amido~enam-3-carbox~lic Acid p-Nitroben ~ 1 Ester
A mixture of (lS,3S,5R,6R) 2,2-dimethyl-6-[3-(2,6-
dichlorophenyl)-5-methyl-4-isoxazolyllamidopenam-3-car~oxylic
acid-l-oxide p-nitrobenzyl ester ~6.21 g, 10.0 mmol) and
trichloroacetyl isocyanate (3.3 ml, 32 mmol) in dioxane
(50 ml) was refluxed for 3.5 hc~rs under nitrogen. The
light yellow solution was cosled, and concentsated to an
oil which wa~ stirred with methanol (100 ml~. The methanol
solution was decanted, with a methanol wash (2 x 10 ml),
from a little residual oil, and was adjusted to pH 7.4 with
5% godium bicarbonate. The pH was held at 7.4 to 7.5 with
3% sulfuric acid for 2 hours and the reac~ion was quenched
in methylene chloride (200 ml) and water tlOO ml). The rich
orga~ic layer was washed with water (100 ml), combin~d with
a back extract (ClI2C12, 50 ml), dried (4A sieves), polish
filtered, and concentrated in vacuo to a yellow oil.
Chromatography of the oil on silica gel (500 g) with
methylene chloride:acetone, (9:1; v:~) gave four zones.
Following the void volume, fractions of 25 ml were collected;
t~bes 6-16 containing the ~3 3-methylcephem, tubes 10-18
small amounts of starting sulfoxide, tubes 20-44 the title
penam, and tubes 46-74 the corresponding cepham. Tubes 21-40
of the penam fraction were combined and concentrated in
vacuo to a clear light cream foam; 29.7% yield (1.97 g):
-58-
7~:~3
n~r 100 MHz ~CDC13) ppm 8.13 (2, d, J = 8.5 Hz, 1/2 aromatic
AB pNB), 7.53 (d, J = 8.5) with 7.47 (tight m, total 5~ 1/2
aromatic AB and dichlorophenyl H's), 6.37 ~1, d, J = 9.2,
C6-NH), 5.80 ~1, dd, J - 4.0, 9.2, C6-~), 5.55 ~1, d, J = 4.0,
C5-H), 5.37 and 5.20 (2, d's, J = 12.8, pNB methylene AB),
5.0 ~2, br ~, NH2), 4.68 (1, s, C3-~), 4.10 (1, d, J ~ 11.5,
1/2 AB C2-CH~O), 3.56 ~1, d, J - 11.5, 1/2 AB C2-CH2), 2.81
(3, s, isoxazolyl CH3), 1.37 (3, s, C2-CH3).
Example 13
(2R,3S,5R,_6R) 6-(4-Nitrobenzvloxycarbonvl)amino-2-
carbamoyloxYmethYl-2-methylpenam-3-car~oxy
Acid p-Nitrobenzvl Ester
A mixture of (lS,3S,5R,6R) 6-(4-nitrobenzyloxycarbonyl)-
amino-2,2-dimethylpenam-3-carboxyllc a~id-l-oxide p-nitrobenzyl
ester (8.19 g, 15.0 mmol), trichloroacetyl isocyanate (5.0
ml, 7.9 g, 42 mmol) and dioxane (75 ml) was refluxed under
nitrogen for 3.5 hours and concent~ated ln vacuo to a light
brown oil. The oil was stirred with warm methanol ~150 ml)
for 0.5 hour a~d the solution was decantPd from a small
amount of dark re~idue. The methanol solution was adjusted
to pH 7.4 with 5% sodium bicarbonate and held at pH 7.4-7.5
with 3% sulfuric acid during a 2.0 hour stirring period.
The mixture was ~hen distributed between methylene chloride
~250 ml) and water (100 ml). The organic layer was washed
with water (100 ml), combined with a CH2C12 back-~xtract
(100 ml), dried (4A molecular sieve), poli~h filtered, and
concentra~ed in vacuo to a light brcwn oil.
_ __
59-
~L5~3
The oil was hromatographed on silica gel ~SOQ g) with
methylene chloride:acetone ~9:1 v:~) to give three major
bands; (in elution order) the ~3-3-methylcephem, the title
penam and the corresponding cepham. The penam fraction was
concentrated in vacuo to a pale yellow foam in 19.7% (1.74 g)
overall yieldt nmr 100 MHz (CDC13) 8.23 (d, J = 9.5 Hz) with
8.18 ~d, J - 8.5, total 4, 1/2 (2) aromatic AB's), 7.55
(d, J = 9.5) and 7.50 (d, J = 8.S, total 4, other 1/2 (2)
aromati~ AB's), 6.36 (1, d, J = 9-5~ C6-N~, 5.63 (1, d,
J - 4, C5-~), Ç.48 (-1, dd, J = 4~ 9-5~ ~6-~)' 5.31 (m) and
5.24 (s, -4, pNB methy}enes~, 5.10 (-2, br s, N~2), 4.73
(1, s, C3-U), 4.25 (1, d, J = 12, 1/2 C2 methylene AB),
3.94 (1, d, J = 12, other 1/2 C2CH2O A~), and 1.44 (3, g,
C~3). Recrystallization of a portion from ether-methylene
chloride returned ~mall colorles~ needles: mp 80-81.
nal. Calc'd for C24H23N5llS C, 48-89~ H~ 3.93; N~ 11-88-
Found: C, 48.82; H, 3.97; N, 11.86.
Example 14
(2~,3S?5R,6R) 6-Amino-2-carbamo~loxymeth~1-2-
meth~lpenam-3-car~oxylic Acid
A suspension of 10% palladium on charcoal (0.50 g)
in ethyl acetate (25 ml) and aqueous potassium bicarbonate
(0.4%, 22.5 ml, 0.10 g inorganics) waR prehydrogenated at
50 psi hydrogen for 15 minutes. The suspension was charged
under nitrogen with t2R~3s~5R~6R) 6-t4-nitrobenzyloxycarbonyl)-
amino-2-carbamoyloxymethyl-2-methylpenam-3-carboxylic acid
-60-
~57~3
p-nitrobenzyl ester (0~54 g, 0.9 mmol) and the whole was
shaken at 50 psi hydrogen pressure for 1.2 hours, The
m~ture (pH 5.0) was centrifuged and the aqueous phase was
washed with methylene chloride (2 x 15 ml), combined with a
water back extract (10 ml), and concentrated to about a 2
ml volume. The rich aqueous phase was diluted with deuterium
oxide (4 ml) frozen on dry-ice and lyophilized to give a light
yellow solid (0.25 g; theory = 0.25 g + inorganics 0.10 g) in
66% product yield; nmr 100 MHz (D20) pp~ ~.63 (1, d, J = 4.0
Hz, C6-H), 4.46 (1, s, C3-H), C5-~ under ~OD, 4.18 (1, d,
J - 11.5, 1/2 AB C2-CHH-0), 4.01 (1, d, J = 11.5, C2-C~HO),
and 1.53 (3, s, C2-CH3).
E
S ~
(3S,4R,6R,7R) 7-~4-Nitrobenz~loxycarbonyl)-
amino-3-carbamoy~ xy-3-methYlcepham-4-carboxylic
Acid p-~itrobenzYl Ester
The title c~mpound was eluted as the final fractions
in the chromatographic separation of ~xample 13 in a yield
of 1.1~ (0.10 g). The product was equal in nmr and tlc
characteristics to an analytical sample prepared in a larger
run: mp 79-80; nmr 100 MHz tCDC13) ppm 8.23 (d, J = 9.0 HZ)
with 8.17 (d, J = 8.5, total 4, 1/2 aromatic AB's p-N02benzyl),
7.55 (d, J a 8.5) with 7. 5a (d, J = 9.0, total 4, 1/2 aromatic
AB's), 6.47 (1, d, J = 9.5, C7-NH), 5.31 (s) and 5.22 (s)
over 5.5-5.2 (m's, total 8, benzyl CH2's over C6H, C7-H
and NH2), 4.89 (1, s, C4-H), 3.54 (1, br d, J = 14.5, 1~2 AB
-61-
~7~3
C2HH), 3.29 (1~ d, J = 14.5, C2HH), and 1.53 (3, s, C3-CH3).
24H23NsO11S-1/2H2O: C, 48.15; H, 4 04;
N, 11.70; S, 5.36.
Found: C, 48.24; H, 3.96;
N, 11.68; S, 5.20
Example 16
6R,7R) 3-MethYl-7-~henoxyacetamidocePh-3-~m
4-carboxylic Acid Diphenvlmethvl Ester
A solution o~ (lS,3S,SR,6R) 2,2-dimethyl-6-phenoxy-
ac~tamidopenam-3-carboxylic acid-l-oxide diphenylmethyl
e~ter monohydrate (5.51 g, 10.0 mmol~ in dioxane (50 ml)
was stirred over Linde 4A molecular sieves ~2 g) for 16
hours and filtered with a dioxane wash (2 x lS ml). To
the dried solution was added p-toluenesulfonyl isocyanate
(4.3 g, 22 mmol), and the mixture was heated at reflux for
7 hours under nitrogen and then concentrated in vacuo to a
light orange oil. The residue was distributed ~etw~en
methylene chloride (50 ml) and water-ice (50 ml) with pH
adjustment to 8.4 using dropwise addition of 50% NaO~I, and
-62-
~75~3
back washes with C~2C12 (20 ml) and pH 10 phosphate buffer
(20 ml). The combined organic extracts were dried (sieves),
po:Lish filtered, and concentrated ~n vacuo to a light yellow
fo~m. The foam was taken into boiling isopropanol (75 ml)
and after cooling yielded a glassy solid (6.23 g). A majox
portion of the solid (5.95 g) was filtered through silica
gel (25 g) with CH2C12:acetone, 9:1, v/v (120 ml) and the
filtrate was concentrated in vacuo to a pale yellow solid
(4.02 g, 78%). Crystallization of a portion (2.72 g) from
isopropanol (40 ml) returned an off-white microcrystalline
solid which was collected, washed with O isopropanol (25 ml)
and dried in vacuo to give the title compound (1.93 g, 71%
recovery, 55~ overall). NMR indicated 82% purity, with
impurities of p-toluenesulfonamide and isopropanol.
Exam~le 17
6R,7R) 3-Meth~l-?-phenox~acetamidoceph-3-em-4-
carboxvlic Acid D~phenylmethyl Ester
A solution of (lS,3S,SR,6R) 2,2-dimethyl-6-phenoxy-
acetamidopenam-3-carboxylic acid-l-oxide diphenylmethyl
ester monohydrate in dioxane was dried over Linde 4A
molecular ~ieves and an aliquot (18 ml, ~ontaining 4.1 mmol
of the ester) was charged with pyridine (0.081 ml, 1.0 mmol),
acetyl bromide (0.073 ml, 1.0 mmol), and acetyl isocyanate
(1.1 ml, 12 mmol). The solution was heated at reflux under
nitrogen for 4 hours and concentrated ln vacuo to a brown
-63-
~S7~313
glass which was filtered through silica gel ~12 g) with
9::L, v/v methylene chloride:acetone (75 ml) to remove color
and impurities. The filtrate was concentrated in vacuo to
a yellow foam (1.85 g, 88%). A portion of this solid (1~61
g) was crystallized from hot isopropanol (20 ml) to return
the title compound as a yellow solid (1.51 g, 94% recovery,
83% overall) of 90+~ purity by n.m.r..
ExamPle 18
(2~,3S,5R,6R) 6-Amino-2-carbamoyloxymethyl-2-
meth 1 enam-3-carbox lic Acid -Nitrobenz 1 Ester
Y P Y P _ Y
A solution of (2R,3S,5R,6R) 2-(N-acetyl)carbamoyloxy-
methyl-2-methyl-6-phenoxyacetamidopenam-3-carboxylic acid
p-nitrobenzyl ester (1.17 g,2.0 mmol) in methylene chloride
(10 ml) at -40 was charged with dimethylaniline (1.03 ml,
8.0 mmol) and phosphorous pentachloride 10.92 g, 4.4 mmol).
The solution was stirred at -35 to -40 for 30 minutes and
cold t--35) methanol (4.1 ml, 100 mmol) was added dropwise.
The pale green solution was stirred at -~5 to -40 for 2
hours and then quenched into ice-water (10 ml). The pH was
adjusted to 1.7 with conc. ammonia and the layers were
separated. The aqueous was washed with CH2C12 (5 ml), combined
with a water back-extract (5 ml), and stirred with CH2C12
(10 m}) during pH adjustment to 6.5 with ammonia. The
organic phase was withdrawn, washed (5 ml, H2O), combined
with a bac~-extract (CH2C12, 10 ml), dried (4A sieves), filtered,
-64-
~57C~:~3
concentrated to 4 ml and diluted with heptane (10 ml~. The
suspension was conoentrated to 8 ml and the liquids were
decanted. The solids were treated with CH2C12 ~4 ml) and
heptane tlO ml) in the same fashion, and the product was
washed with heptane and dried to an off-white solid (0.28 g)
34%; nmr 100 MHz CDC13-D20 ~ 8.24 (2, d, J - 8.5 IIZ, 1~2
pNB AB), 7.56 (2, d, J = 8.5, pNB AB), 5.6B (1, ~rd J = 4,
C5-~, 5.32 (2, s, benzyl C~2), 4.76 (1, s, C3-II) 4.55 (~OD
overlapping C6-H d), 4.16 and 3.97 (2, ABq J = 11.5 C2-CII2-0),
1.43 (3, s, C3-C~3), wi~h 2.36 (3/4, s, ~CH3 of impurity W-
acetyl analog; -25 mol %).
Example lg
(6R,7R) 3-Methyl-7-phenoxvacetamidoceph-3-em-4-
carbox~lic Acid DiphenYlmethyl Ester
(lS,3S,5R,6R) 2,2-Dimethyl-6-phenoxyacetamidopenam-3-
carboxylic acid-l-oxide diphenylmethyl ester (25.00 gms,
45.41 mmoles) was dissolved in sieve-dried, peroxide-free
dioxane t250 mls) at 25C with good agitation. To this
solution, in order, were added pyridine (10.99 mls, 10.78
gms, 136~22 mmoles), acetyl bromide (0.67 mls, 1.12 gms,
9.08 mmoles) and dLmethylsilyl diisocya~ate (16.14 gms,
113.51 mmoles), and the slurry was heated to reflux (ca.
100C) for 4 hours. The dioxane slurry was then cooled to
25C, filtered, and concentrated in vacuo at 50C to a heavy
oil. The oil was taken up in methylene chloride (400 mls),
-65-
stirred for 15 minutes at 25C, filtered, and concentrated
in vacuo to dryness. The residue was dissolved n hot
l-butanol (500 mls, ca. 90-95C) and allowed to cool to
25ClC. The slurry was cooled to 0-5C for 16 hours, filtered,
wa~hed with cold butanol (0-5C, 100 mls), then with
*
Skellysolve B (200 mls), and oven-dried at 45C to constant
weight. Yield: 20.2 gms, 86.4% of snow-white crystalline
title compound. The NMR spectrum was clean and consistent for
~he desired structure, as follows:
~ MHZ H' NMR, ~(CD2C12) 2.08 (3~,s,CH3~, 3.04-3.62 (2H, m,
CH2, JABz18.1 Hz), 4.55 (2H, s, CH2), 4.99-5.05 (1~, d~ ~-
lactam H, JA=4.7 Hz), 5.74 5.91 (lH, m, ~-lactam H, J - 4.7
Hz), 6.75-7.50 (17~I, m, aromatic C~I, and NII).
Example 2a
(6R,7R) 3-Methyl- _PhenoxYacetamidocePh-3-em-4-
carbox~lic Acid Diphen~lmethYl Ester
(lS,3S,SR,6R) 2,2-Dimethyl-6-phenoxyacetamidopenam-3-
carboxylic acid-l-oxide diphenylmethyl ester (55.06 gms,
100.00 mmoles) was dissolved in sieve-dried, peroxide-free
dioxane (550 mls) at 25C with good agitation. To this
solution, in order, were added pyridine ~24.21 mls, 23.73
gms, 300.00 mmoles), acetyl brom~ide (1.48 mls, 2.46 gms,
20.00 mmoles) and methylsilyl triisocyanate (89% pure,
21.30 mls, 25.-~4 gms, 133.33 mmoles). The slurry was heated
to reflux (ca 100C) for 4 hours. The reaction mixture was
then cooled to 25C and filtered, with the clear yellow
*Trade Mar~ -66-
~L57~3~3
fiLtrate ~eing concentrated in vacuo at 50C to a highly
vi~scous oil~ The oil was dissolved in hot 2-propanol (-80C,
3000 mls), filtered, and allowed to cool to 25C. The slurry
was cooled to 0-5C for 2 hours, filtered, and washed with
2-propanol (0-5C, 400 mls), and oven dried at 45C to constant
weight. Yield: 38.6 gms, 75~ of white crystalline title
compound. The 80 MHz H' NMR spectrum was clean and consistent
for the desired structure.
Example 21
(2R,3S,5R,6R) 2-~N-Acetyl)carbamoYloxy~ethyl-6-amino-2-
met ~ lic Acid P-Nitrobenzyl Ester
A solution of (2~,3S,SR,6R) 2-(N-acetyl)carbamoyloxy-
methyl-2-methyl-6-phenoxyacetamidopenam-3-car~oxylic acid
p-nitrobenzyl ester (4.68 gm, 8 mmols) in dry methylene
chloride (40 ml) was cooled to -60 under nitrogen. It
was charged with dimethylaniline (4.06 gm, 33.5 mmol) and
phosphoxus pentachloride (3.68 gm, 17.7 mmol) and stirred
for 30 minutes at -64 to -56, during which time the phosphorus
pentachloride dsssolved. ~ solution of dry methanol (8.10
ml) in dry methylene chloride (8.10 ml) was then slowly added
at -55 to -45. The reaction mixture was stirred for 20
minutes at -60 to -55 and then poured into 16 ml of ice-
water. The pH was adjusted to 1.7 with concentrated ammonia
and the layers were separated. The methylene chloride layer
was washed with 20 ml of pH 2.0 buffer which wa~ separated
and combined with the aqueous layer. Methylene chloride
-67-
7(~3
(20 ml) was added to the com~ined aqueous layers and the
mixture was adjusted to pH 6.5 with concentrated ammonia. The
phases were separated, the water was washed with 20 ml of
me~hylene chloride, and the combined methylene chloride layers
were dried over molecular sieves. After filtration, the
solution was concentrated in vacuo to about 20 ml and then
added dropwise to 400 ml of stirring heptane. The heptane was
decanted from the solid which precipitated and was replaced
by 100 ml of fresh heptane. The suspension was thoroughly
stirred, filtered, washed, air dried, and finally dried in
vaUo. There was obtained 1.66 gm of the title product as a
white amorphous solid. The purity was estimated from its nmr
spectrum to be about 90%, the remainder being primarily the
non-acetylated material.
Example 22
(~R,3S,5R,6R~ 2-(N-Acet~l)carbamoyloxymethyl-6-amino-2-
methyl~enam-3-carboxvlic Acid
To a prehydrogenated suspension of 10% palladium on
carbon (O.B3 ym), water-washed ethyl acetate (8.3 ml) and
water (4.1 ml) was added (2R,3S,5R,6R) 2-(N-acetyl)carbamoy-
loxymethyl-6-amino-2-methylpenam-3-carboxylic acid p-nitro-
benzyl ester (0.83 gm, 1.84 mmol). The mixture was ~haken
at 50 psi hydrogen pressure-for 80 minutes and filtered
through Dicalite-coated paper. The aqueous phase was
separated, concentrated at reduced pressure to remove volatile
solvent and gases, frozen and lyophilized. There was obtained
0.38 gm of the title compound as a white amorphou~ solid.
Its nmr spectrum was consis.ent with the desired product.
*Trade Mark
-68-
~7~3
Example 23
(2R,35,5R,6R) 2-(N-Acetyl)carbamoyloxymethyl~6-E !R) -2-Amino-2-
enylacetamido]-2-methYl~ena_-3-carboxylic Acid p-Nitro-
benzYl Ester
A solution of (2R,3S,SR,6R) ~-(N-acetyl)carbamoyloxy-
methyl-6-amino-2-methylpenam-3-carboxylic acid p-nitrobenzyl
ester (0.80 gm, 1.77 mmol) in methylene chloride (10 ml) was
cooled to 2 and dimethylaniline (0.214 gm, 1.77 mmol) was
added. To the stirred mixture was added (-)-phenylglycyl
chloride hydrochloride (0.3g2 gm, 1.83 mmol) in kwo equal
portions. The first portion was added at 2 and the reaction
m~xture was gradually warmed to 20 over a 90 minute period.
The reaction did not appear to begin at the lower temperatures.
The second portion of the acid chloride was added at 20 and
the reaction mixture was stirred at room temperature for
4-1/2 hour~. Water ~10 ml) was added and, with thorough
mlxing, the p~ was adjusted to 1.7. The layers were separated,
the water layer was washed with methylene chloride, and the
methylene chloride layer was washed with pH 2.0 buffer. The
aqueous layers were combined, adjusted to pEI 7.0 with 10%
KOH solution, and extracted with methylene chloride (2 x 10
ml). The methylene chloride extracts were combined, dried
over molecular sieves and concentrated in vacuo to about 15 ml.
This solution was added dropwise to 300 ml of stirring heptane
and produced a fine white amorphous solid. This was removed
by filtration and dried to give 0.61 gms of the title product.
The purity was estimated from its nmr spectrum to be about
60~.
-69-
~7~3~3
Exam~1e 24
(,2R!3S,5R,6R) 2-(N-Acetvl)carbamoyloxymethyl 6-[(R~-2-
_mino-2-phenylacetamidol-2-meth~l~enam-3-carboxvlic Acid
To a prehydrogenated suspension of 10% palladium on
carbon (O.S9 gm), water-washed ethyl acetate (6.0 ml) and
water (3.0 ml) was added (2~,3S,SR,6R) 2-(N-acetyl3carbamoy-
loxymethyl-6-[(R)-2-amino-2-phenylacetamidoi-2-methylpenam-
3-carboxylic acid p-nitrobenzyl est~r (0.59 gm. 1.06 mmol~.
The mixture was shaken at 50 psi hydrogen pressure for 3
hours at 25 and then filtered through Dicalite-coated paper.
The aqueous phase was separated, co~centrated at reduced
pressure to remove volatile solvent and gases, frozen and
lyophilized. There was obtained 0.30 gm of the title compound
as an amorphous solid. The purity was estimated from its
nmr spectrum to be 60-70%.
Example 25
Percentage Of Penam, CePham And Cephem Formed In The Reaction
Of [lS,3S,5R,6R] 2,2-Dimethyl-6-phenoxyacetamidopenam-3-
carboxylic Acid-l-oxide Di~henylmethYl Ester With Different
Isocyanates Under Var~ing Conditions And With Varving
Subsequent Treatment Of The Initial Product
-
A 5% solution of [lS,3S,5R,6R] 2,2-dimethyl-6-phenoxy-
acetamidopenam-3-carboxylic acid-l-oxide diphenylmethyl ester
in di'oxane was prepared. Aliquots of the above solution
containing 5.51 gms (10 mmols) of the penicillin sul~oxide
ester were charged with 30 mmols (300 mole %) of the indicated
--7 0--
~ ~S7~3
isocyanate (and, where indicated, with pyridine and/or acetyl
bromide). The solutions were refluxed under nitrogen for
4 hours and then concentrated in vacuo to dryness. When
indicated, portions of the resulting products were further
treated with base or filtered through silica gel with methylene
chloride:acetone (9:1, v:v), and concentrated to dryness.
The residues were analyzed for approximate percentages of
penam, cepham and ~3-cephem by integration of the nmr methyl
group signals at ca. ~1.2 for the penams, ca. ~1.5 for the
cephams and ca. ~2.11 for the ~3-ceph~ms.
Mole % Mole % % % %
Pyridine C~3CBr Penam Cepham Ceph~m
p-ToluenesulfonYl isoc~anate
(a) 0 0 57 41 2
(b) Product of (a) treated 0 7 93
in methylene chloride
with tetramethylguan-
idine; latter then
removed with water
washes.
(c) Product of ta) 0 92 8
filtered through
silica gel.
Methanesulfonyl isocyanate
(d) 0 0 63 27 10
(e)ao 0 57 9 34
(f)53 0 50 0 50
(g) Product of (f) 15 0 85
filtered through
silica gel-
(h) Product of (d) in 10 20 70
methylene chloride
washed with pH 8.5
water and held 2 hrs.
(i) Product of td) 55 o 45
treated in methylene
chloride witll dimethyl
formamide; latter
removed with water
washes.
(j~ Product of ~d) 45 30 25
filtered through
silica gel.
Trichloroacetvl isocvanate
(k) 0 0 26 56 18
Acetvl isocYanate
(1~ 0 0 7~ 25 5
(m)50 0 70 25 5
(n)0 20 68 30 2
(o)25 25 0 10 80
MethoxycarbonYl isoc~anate
(p) 0 0 37 38 0
Note: Product (o) also contained about 10% of an
unidentified impurity appearing at ca. ôl.6.
Product (p) also contained about 25% of an unidentified
impur~ty appearing at ca. ~1.9.
Exam~le 26
Preparation of f6R,7R] 3-Methyl-7-phenoxyacetamidoceph-
3-em-4-carboxvlic Acid Diphenvlmethyl Ester From ~lS!3S~5R,6R]
2 ! 2-Dimethyl-6-PhenoxyacetamidoPenam-3-carboxYlic Acid-l-ox _ e
Diphenylmethyl E~ter Utilizing Various IsocYanates And Varyinq
Amounts of Pyridine And Ace ~l_Bromide as Catalysts
A solution of 55 gm (100 mmol) of [lS,3S,5R,6R] 2,2-
dimethyl-6-phenoxyacetamidopenam-3-carboxylic acid-l-oxide
diphenylmethyl ester in dioxane (500 ml) was dried over
Linde 4A sieves (50 gm). Aliquots (25 ml each; 5 mmols)
were withdrawn, charged with 15 mmoles (300 mole ~) of the
-72-
~S~;~013
indicated isocyanate and the indicated mole percentage of
pyridine and acetyl bromide. The solutions were refluxed
under nitrogen for 6 hours and then concentrated in vacuo
to dryne~s. The residues wexe filtered through silica gel
(:LO gm) with methylene chloride:acetone (9:1; v:v). ~he
f:iltrates were concentrated in vacuo to light yellow foams
which were analyzed by liquid chromatography against authentic
[6R,7R] 3-methyl-7-phenoxyacetamidoceph-3-em-4-carboxylic
acid diphenylmethyl ester as a standard. Listed below are
the % weight yield, % activlty and % activity yield for each
reaction.
Mole ~ Mole % ~ Weight % % Activity
Pyridine CH3CBr Yield Activity Yield
.. ~
Methanesulonvl isocYanate
10 5 110 47.2 52
30 25 110 47.8 53
50 25 130 37.5 49
~00 50 120 27.6 33
TrichloroacetYl isocvanate
20 10 9S 37.4 36
25 20 165 28.2 48
50 25 110 41.3 45
Silicon tetraisocyanate
-
120 43.2 52
120 51.0 61
