Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
~765~7
BACKGROUND OF THE INVENTION:
This invention relates to new routes for the
synthesis of 3',4'-dideoxykanamycin B which is anti-
bacterial against a variety of gram-positive and gram-
negative bacteria and particularly effective in inhibiting
kanamycin-resistant organisms such as kanamycin-resistant
Staphylococci and kanamycin-resistant Escherichia coli.
DESCRIPTION OF THE PRIOR ART:
.
~ 3',4'-Dideoxykanamycin B having the structure:
"
., .
Ç~2NH2 ~H2 ' ~ `
" ~ ~ ,, 6 '
; N~
HOCH2 j
4~ ~ 0
Ho
.~ 3" l2
OH
' 10
has hitherto been prepared by a method comprising pro-
.; tecting the ~iYe amino groups and all or a part of the
hydroxyl groups other than 3'- and 4'-hydroxyl groups
of kanamycin B by a conventional method, sulfonylating
the 3'- and 4'-hydroxyl groups to afford a derivative
having 3l_ and 4'-disulfonic ester groups, removing the
3'- and 4'-disulfonic ester groups by known methods to
give a 3',4'-unsaturated compound, reducing the 3',4'-
- 2
~76~;7
unsaturated compound and removing the residual protecting
groups. The known method requires nine steps from kana-
mycin B to 3',4'-dideoxykanamycin B (see British Patent
Specification No. 1~349,302). Further, the method re-
quires the use of sodium iodide and zinc powder in large
amounts in the step for removing the 3'- and 4'-disulfonic
ester groups, thus involving questions of iodine resources
and of environmental pollution resulting from disposal
of by-products. Therefore, the development of new, more
advantageous method for synthesls of 3',4'-dideoxykanamycin
B has eagerly been desired from the industrial point of
view.
SUMMARY OF THE INVE~TION: -
~ .
It is khe primary object of this invention to pro-
vide some new routes for the synthetic preparation of 3',
4'-dideoxykanamycln B which are advantageous over the
prior art in that they do not use an alkali metal bromide
or iodide and z:inc powder~ but use other reagents of less ~-
expenses~ All the new processes originate from kanamycin
.
B as in the prior art but pass through a new route of
,-; reaction.
Accord~ng to a first aspect o~ this inventjon~
there~ore~ there is provided a process for the preparation
; of 3~,4'-dideoxykanamycin B or its acid addition salts and
int~n~ia~es th~f o~prising one or more of the ~oll~ng steps:
(1) treating with a xanthate a 3',4'-epoxy derivative of
an amino- and hydroxyl-protected kanamycin B of the formula:
.,
', ' ' :,, '
:
5~7
CH2~HCOOR ~HCOOR
/ ~ ~ ~HCOOR
(~-~ ~ .'
~HCOOR
OCH2! (I)
Z~o~
~ .
: wherein R represents a hydrogen atom or an alkyl or aryl
group, Z represents an alkylidene, arylidene, cyclohexyli-
: dene or tetrahydropyranylidene group and the 3',4'-epoxy
group is in ~- or ~-position whereby to form a 3'~4'- - .
dideoxy-3'-eno-kanamycin B derivative of the formula:
CH2N~COORI ~HCOOR
; ~ o
~HCOOR
/ (lI)
, ~ /
~ OCH2 O
Z\/~
. ~H
wherein R and Z have the same meaning as defined above
together with a 3',4'-episulfido-kanamycin B derivative
of the formula:
CH2NHCOOR ~HCOOR
~ =jl~COO~
~HCOOR
: OCH2
., ~
wherein R and Z have the same meaning as defined above -
and the 3'~4'-episulfide group is in a- or ~-position;
~: ~ (2) isolating the 3',4'-dideoxy-3'-eno-kanamycin B
~- derivative ~rom the reaction mixture; ~ ~-
~ (3) removing the amino-protecting groups -COOR and
-- 10 hydroxyl-protecting group Z of the 3'~4'-dideoxy-3'-eno :
derivative thus isolated in a conventional manner to
form 3',4'-dideoxy-3'-eno-kanamycin B of the formula:
. .
,~ :
' .
~9765~7
CiI2 ~Hz
NH
= o _~
NH2
HOCH2 o ( IV )
~0 /
K~
HO \~/
OH ` . .
.` .
and (4) hydrogenating the compound thus formed in a
conventional manner to form 3' 3 4'-dideoxykanamycin B;
and, if desired, converting the compound thus formed
into an acld addition~salt thereof.
The step (1) of the first aspect process of this
invention, that is the treatment of a 3',4'-epoxy deriv-
ative of the formula (I) in either ~- or ~-form~with a
xanthate, may be effected in an organic solvent, pref-
erably at a temperature of 50~100C. The~organic
solvent may preferably be a lower alkanol such as methanol
and ethanol. The xanthate to be used foP this treatment
- may be those of~the formula R'OCSSMe where R' is a lower
alkyl group, Me is an alkali metal such as sodium or
potassium. Generally, this reaction gi~es a 3'~4'-
dideoxy-3'-eno derivative of the formula (II) as~a first
product in admixture with a 3',4'-episulfide derivative
of the formula (III) as a second product after washing
656~7
the reaction mixture with water, recovering the solvent
by distillation and concentrating the residue to dryness.
The mechanism of reaction between the 3',4'-epoxy
derivative of the formula (I) and the xanthate has not
yet been made clear, but a presumable possibility is that
the conversion of 3',4'-epoxy derivative into correspond-
~- ing 3',4'-dideoxy-3'-eno derivative of the formula (II)
proceeds via corresponding 3',4'-episulfide derivative
of the formula (III).
The isolation of the first and second products of
the step tl) from each other, i.e. the step (2) of the
first aspect process, may~be effected, preferably by
chromatography, for example silica-gel thin layer chromato-
graphy in a usual manner, for~example using a mixture
(e.g. 1:1 by volume) of carbon tetra¢hloride and acetone
as developer.
..
The step (3) of the first aspect process of this
ln~ention for the removal of the amino-protecting~groups
-COOR and~hydroxyl-protecting group Z may be carried out
.
'`! 20 in a usual manner. For example, the removal of the
~ hydroxyl-protecting group Z may first be effected by a
:: .
mlld hydrolysis with a dilute hydrochloric acid or an~ ;
aqueous acetic acid and then the amino-protecting groups
may be removed by a hydrolysis with barium hydroxide or
by hydrogenolysis in the presence o~ a palladium catalyst.
The step (4) of the first aspect process, that is the
hydrogenation step, may be carried out in a known manner.
Thus, a catalytic reduction with hydrogen in the presence
of a known hydrogenation catalyst comprising a platinum
; 30 group metal such as platinum or palladium may preferably
,~
- - 7
76~7
be applicable to the step (4). Raney nickel catalyst
may also be used for this purpose.
The first aspect process of this invention is
advantageous over the prior art process above-mentioned
in that
- the formakion of 3',4'-unsaturation can be
achieved without relying on the reaction involving
the use of an alkali bromide or iodide and zinc
powder;
- as the ~inal intermediate compound which is to
~e converted to the desired product, 3',4'-
dideoxykanamycin B, in the last step, 3',4'-
dideoxy-31-eno-kanamycin B, i.e. the compound
of the formula (IV) free from any protecting
group can be obtained,
- in the last skep, the catalytic hydrogenation
can be achieved relatively easily with much less
impurities derived from reagents used, so that
the purification of the final product is required
only to a less extent than in the prior art
process wherein the step for removing amino- and
hydroxyl-protecting groups is carried-ouk after
- the step for the hydrogenation.
It will be appreciated, however, that the order of
the steps (3) and (4) of the first aspect process of this
invention can be reversed, if desired$ to ~ollow the known
order adopted by the prior art process.
The final product, 3',4'~dideoxykanamycin B in free
base form, may be converted, if desired, to an acid addition
salt derived from an inorganic or organic acid. ~or example,
-- 8
~7~5~;~
sulfate of 3',4'-dideoxykanamycin B may be obtained by
adding dilute sulfuric acid to an aqueous solution of the
free base to adjust the pH value to 6.8, treating the
solution with decoloring carbon, filtering the solution
~; and freeze-drying the filtrate.
~, We have further found that the 3',4'-episulfide
; derivative of the formula (III) which is formed as second
product in the step (1) of the first aspect process of
this invention is also useful as intermediate for the
preparation of 3',4'-dideoxykanamycin B. Our discovery
~' : in this respect is that there are two routes for converting
the 3',4'-episulfide derivative of the formula (III) to
a known useful intermediate for the preparation of 3',
4'-dideoxykanamycin B; the first route is to treat the
3',4'-episulfide derivative with an acid to form 3',4'- :
dideoxy-3'-eno-kanamycln B of the formula (IV) and the
second route is to treat the 3!,4'-episulfide deriva'ive
with hydrazine or Raney nickel to form a 3',4'-dideoxy- : :
, 3'-eno-kanamycin B derivative of the formula (II).
According to a second aspect process of thls
invention, therefore, we provide a process for the prepara-
tion of 3',~'-dideoxykanamycin B or its acid addi~ion saltsand
Ln~E~ates thereof o~prising one or more of the follo~ng steps:
(1) treating with a xanthate a 3',4'-epoxy deriyative of
an amino- and hydroxyl-protected kanamycin B of the formula:
' ' '
'
~765i~7
CH2~HCOOR ¦ ~XCOOR
NHCOOR
~0~0~
NHCOOR
OCH2 (I)
Z-/o~
OH
. ' .
~: wherein R represents a hydrogen atom or an alkyl or aryl
group, Z represents an alkylidene, arylidene, cyclohexylidene
or tetrahydropyranylidene group and the 3' 3 4'-epoxy group
is in ~- or ~-position whereby to form a 3',4 ' -episulfido-
kanamycin B derivatlve of the formula:
C~2~HCOOR
~HCOOR
/ ~ NHCOOR
', ' S~ ~0 J\~ ~ ~:
NHCOOR
(III)
, OH
- 10
:'''' ~' ' :
71~i567
wherein R and Z have the same meaning as defined above
and the 3',4'-episulfide group is in ~- or ~-position
- together with a 3',4'-dideoxy-3'-eno-kanamycin B derivative
of the formula:
CH2NHCOOR ¦ NHCOOR
~ NHCOOR
' ~ O ~> .
`,~ :'
~XCOOR
OCH2 (II) :
Z~/~
OH
wherein R and Z have the same meaning as defined above;
(2) isolating the 3',4'-episulfido-kanamycin B derlvakive
from the reack-ion mixture,
: (3~ treating the 3',4'-episulfide derivative thus isolated
. . .
: with an acid to form 3',4'-dideoxy-3'-eno-kanamycln B of
the formula:
'''
-- 11 --
- .
5~7
CH2 ~H2 NH2
IIK2
H2
:, /
HOCH2 o ( IV )
2 ~/ :
HO \~/
~ OH
: :
'
and (4) hydrogenating the compound thus formed in a
con~entional manner to form 3',4'-dideoxykanamycin B;
and, if deslred, con~erting the compound thus formed into
an acid addition salt thereof.
The steps (1),(2) and (4) of the second aspect ::
process of this invention correspond to the steps (1),
(2) and (4) of the first aspect process as above-mentioned,
respectively.
The step (3) of the second aspect~process, l.e. the
treatment of the 3',4'-episulfide derivative of the formula
~ (III) with an acid may preferably be carried out in a lower :~ :
alkanol such as methanol and ethanol using a hydrohalogenic : :~
acid such as concentrated hydrochloric acid and hydrobromic
acid. In general, however, a non-oxidiælng mineral acid,
for example sulfuric acid, may be used for this treatment.
~; Preferably, the treatment may be carried out at a tempera- : :
ture of 0~30C. ~ :
- 12
, . . . . . .
:~765~7
According to a third aspect process of this inven-
tion, there is provided a process for the preparation of
3',4'-dideoxykanamycin B or its acid addition salts and
: , in~iates thereof o~rismg one or mDre o the foll~ng steps:
(1) treating with a xanthate a 3',4'-epoxy deri~ative o~ . :
an amino- and hydroxyl-protected kanamycin 3 of the formula:
' :
CH2~HCOOR ¦ NHCOOR
0 ~ ~HCOOR
~0 1~ '
":'
~HCOOR
OCH2 o (I)
Z~
OH
:wherein R represents a hydrogen atom or an alkyl or aryl
. group and Z represents an alkylidene3 arylidene, cyclo-
hexylidene or tetrahydropyranylidene group whereby to form
a 3',4'-episulfido-kanamycin B derivative of the-.fo~mula:
' ' ' : "
' , .
:
. ~,
: 13
65~7
CHzNHCOOR ~HCOOR
~HCOOR
~--\'H"
NHCOOR
/ OCH2 (III)
z/l~ \1/ `
\~
OE
.~
wherein R and-Z have the same meaning as defined above
and 3',4'-episulfide group is in a- or ~-position to~ether
.~ .
~ with a 3',4'-dideoxy-3'-eno-kanamycin B derivative of the
-~ formula:
CH2~HCOORj NHCOOR
NHCOOR
~Y o ~ ~ ,. ,
~HCOOR /
/ (II) ~
OCH2 O :`
Z~
: OH ~
.
: '
.. . ..
~76S6~'
wherein R and Z have the same meaning as defined above;
(2) treating the reaction mixture from the step (l) with
hydrazine or Raney nickel to convert the 3',4'-episulfide
derivative of the formula (III) into a further amount of
the 3',4'-dideoxy-3'-eno-kanamycin B derivative of the
formula (II) above;
(3) removing the amino-protecting groups -COOR and hydroxyl-
protecting group Z of the 3',4'-dideoxy-3 t -eno derivative
- thus formed in a conventional manner to form 3',4'-dideoxy-
3'-eno-kanamycin B of the formula:
. '
','
CH2NH2 NH2
i NH2
/ (IV)
HOCH2 o
~
HO
0
'
and (4) hydrogenating the compound thus formed in a con- :
ventional manner to form 3',4'-dideoxykanamycin B; and,
if desired, converting the compound thus formed into an
acid addition salt thereof.
The steps (1),(3) and (4) of the third aspect process
of this invention correspond to the steps (1),(3) and (4)
of the first aspect process as above-mentioned, respectively.
- 15
.
~ 76~
In the step (2) of the third aspect process, the
treatment with hydrazine may preferably be effected in
a lower alkanol such as methanol and ethanol using hydrazine,
particularly in the form of hydrate NH2NH2-H20~ at room
temperatures, usually 15~-25C. The amount of hydrazine
to be used may preferably be about 10~30 moles per mole of
the compound of the formula (III). The treatment with
Raney nickel~ if adopted for the step (2), may preferably
be carried out by dissolving the compound of the formula
(III) in a lower alkanol, for example methanol, adding
Raney nickel tQ the solution in an appropriate amount, for
example threefold amount in respect of the amount of the
compound of the formula (III) on the weight basis and
maintaining the mixture under stirring at room temperatures,
: usually 15~25C for 1-3 hours
In the third aspect process of this invention, the ~`.
step (2) is also applicabIe, if desired, to the 3',4'-
: episulfide derivative of the formula (III) which has been
isolated from the 3',4'-dideoxy-3'-eno derivative of the
formula (II), but lt 1s usually advantageous to apply the
- step (2) directly to the reaction mixture from the step (1) ~.
containing both the compounds of the formulae (II) and (III)
particularly in large scale operations. ;
We have further found that the 3',4l-dideoxy-3'-
eno derivatives of the formula (IV) can be produced from
the 3',4'-epoxy derivatives of the formula (I) through
another route involving four steps with a high overall
yield. This route comprises the steps of
(1) treating a 3',4'-epoxy derivative of the formula:
6S67
CX2NHCOOR NHCOOR
: , ~ ~ ~ NHCOOR
-: \ ~H~
NHCOOR
O¢H2 O (I)
Z--/o~
: OH
:`
: whereln R and Z have the same meaning as defined above
- with an acylatin~ agent, for example benzoyl chloride3 in
a conventional:manner to acylate the 2"-hydroxyl group,
giving a compound of the formula: :
.
:..
CH2NHCOOR
~HCOOR:
O - ~
NHCOOR
'. r~~
, NHCOOR
~, /
~ / ~ (V)
~ OCH2 O
Z\/~
' OY
~: .
'
,,
~7~i567
wherein R and Z have the same meaning as defined above and
Y represents an acyl group;
(2) treating the compound of the formula (V) thus obtained
with an alkali or alkaline earth metal iodide, for example
sodium iodide, preferably in the presence of sodium acetate
and glacial acetic acid, to give a compound of the formula:
C}I2NHCOOR ¦ NHCOOR
~HCOOR
~ \~
l!JHCOOR
~OCH2 o ( VI )
z<~
OY ~ ~
where R, Z and Y have the same meaning as defined above;
(3) subjecting the compound of the formula tVI) thus
obtained to 3'-O-sulfonylation with a sulfonylating agent ::
such as mesyl chloride, tosyl chloride and benzylsulfonyl
chloride in a known manner, preferably in pyridine at a
temperature below 10C, to form the compound of the formula:
- 18
.
,:
5~
I! CH2~HCOOR ,
NHCOOR
I ~ ~NIIC OR
NHCOOR ~ :
` OCH2 o (VII)
Z\/o~
Y
, ' '
where R, Z and Y have the same meaning as defined above :
- and W represents mesyl~ tosyl or benzylsulfonyl group;
.. . .
. (4) heating the reacti~on mixture from the step (3) above,
preferably to a temperature of 80~100C to convert the
compound of the formula (VII) into the compound of the
; formula:
,: ' .
.
CH2NHCOOR
: ~ NHCOOR
C OR
NHCOOR
: ,
OCH2
/ ~ / (VIII)
~, Z~o~
.` 0~
-- 19
.
56~
wherein R, Z and Y nave the same meaning as defined above;
and (5) treating the compound of the formula (VIII) thus
obtained with an alkali or alkaline earth metal alcoholate,
for example sodium methoxide, in a known manner to give
3',4'-dideoxy-3'-eno derivative of the formula (II) above.
The compound, penta-amino-protected, 4",6"-hydroxyl-
protected, 3',4'-~-epoxy derivative of kanamycin B re-
presented by the formula:
CH2NHCOOR ¦ NHCOOR
O ~
NHCOOR
/ (IX)
OCH2 o - .
Z\/~
OH ~
wherein R and Z have the same meaning as defined above :
which is to be used as starting compound of the first to
; third aspect processes according to this invention is a
: new compound and constitutes another aspect of this
invention.
The new 3',4'-~-epoxy derivative of kanamycin B
of the formula (IX) can be derived from kanamycin B through
several reaction steps as explained below.
First of all, kanamycin B is subjected to amino- :
.
' . , -' ' : : " ~' ' '
., , ~ .
~76~6~
protecting step in a known manner. Thus, kanamycin B is
reacted with a chloroformate of the formula RCOOCl wherein
R represents a hydrogen atom or an alkyl or aryl group
such as phenyl to protect all the five amino groups of
kanamycin B in the form of urethane group -NHCOOR in the
same manner as that described in Japanese Patent Publica-
tion No.7595/75, affording penta-N-protected kanamycin B
of the formula:
'
'
C~2NHCO
NHCOOR
\NHCOOR
HO~
: NHCOOR
' / (X)
HOCX2 O
~0~ ,
Hl\~
OH
,` , . ' ~
wherein R has the same meaning as defined above.
The next step is 4"g6"-hydroxyl-protecting step
which is also carried out in a known manner. Thus, the
compound of the formula (X) may be reacted with a known
hydroxyl-protecting agent selected from an alkylidenating
agent, an arylidenating agent, a cyclohexylidenating agent
and a tetrahydropyranylidenating agent. Typical examples
of such hydroxyl-protecting agent include acetaldehyde,
2',2'-dimethoxypropane, anisaldehyde, benzaldehyde, dimethyl-
- 21
7~5iti'7
acetal, tolualdehyde, l,l-dimethoxycyclohexane and l,l-
dimethoxytetrahydropyran. The reaction may preferably be
carried out in a polar organic solvent, e.g. dimethyl-
formamide in the presence of a catalytic amount of p-
toluene sulfonic acid at room temperatures, for example
15~25C for 15~20 hours This brings the selective in-
troduction of the hydroxyl-protecting group in 4",6"-
positions, thus yielding 4",6"-O-protected derivative of
the formula:
~'"
,:
C~z~ICOOR ~
~HCOOR
\~ HCOOR
HO\~--O--
NXCOOR
( XI )
()CH2 o ~:
Z`~ ~
OH
1 0
wherein R has the same meaning as defined above and Z
represents an alkylidene, arylidene, cyclohexylidene or
tetrahydropyranylidene group. In this selective reaction,
it is desired that the temperature should be kept not to
exceed 30C because there may also occur the attack of the
hydroxyl-protecting agent on the 3'- and 4'-hydroxyl groups ~ -
at higher temperatures.
The compound of the formula (XI) is then subjected
:'
- 22
.
3L~7~ii67
to acylation reaction for the purpose of selective protec-
tion of the 21'- and 3'-hydroxyl groups with hydroxyl-
protecting group of an acyl type. The acylation step may
usually be carried out by dissolving the compound of the
formula (XI) in pyridine, addin~ an acylating agent such
as an acyl chloride under a low temperature condition,
preferably below 5C and maintaining the mixture under
stirring for several hours.
Preferred acylating agent may be an acid chloride
of an alkanoic acid having 2-4 carbon atoms such as acetyl
chloride or an aroyl chloride such as benzoyl chloride.
The use of benzoyl chloride is most preferred. The use
of a temperature below 5C for the acylation step does
not affect the 4'- and 5-hydroxyl groups which are relative-
ly low in reactivity. Thus, 2",3'-diacyl derivative of the
formula:
;.
~HCOOR~NHCOOR
) ~ COO
~ H ~ O
; NHCOOR
/ (XII)
- OCH2 : o
z\/~~
~
OY
wherein R and Z have the same meaning as defined above,
- 23
ii5 fii7
and X and Y each represent an acyl group, for example
an alkanoyl, particularly a lower alkanoyl such as acetyl
or an aroyl such as benzoyl may be produced.
In the acylation step, 2"-monoacylated derivative,
i.e. a compound of the formula (XII), but wherein X re-
presents a hydrogen atom may be obtained, if desired for
some purposes, by conducting the acylation reaction under
a milder conditions. Thus, in case of benzoyl chloride
being used as acylating agent, a major proportion of 2"-
monobenzoyl derivative may be obtained under such condi-
tions that benzoyl chloride is added at a temperature
below 0C slowly and in small parts. On the other hand,
at least a ma~or proportion of 2",3'-dibenzoyl derivative
may be ob~ained when ben~oyl chloride is added at a time
at a temperature between 0C and room temperatures, pref-
erably 0C and 5C. If 2"-monoacyl and 2",3'-diacyl
derivatives are obtained in the form of a mixture, the
isolation of the respective derivatives may be effected
- by a chromatographic separation technique in a known
manner, per se, for example by silica-gel thin-layer
chromatography using 2:1 by volume of chloroform-methanol
as developer.
. .
The compound of the formula (XIIj is then subjected
~; to 4'-0-sulfonylation to form 4'-0-sulfonylated derivative
of the formula:
- 24
.
,
7~ 6'~
CH2N~COOR.
- NHCOOR
~L ~ ICOOEI
NHCOOR
(XIII )
Z~
O ..
,~ oy
.'.~ ~' , ~ .
wherein R, Z, X and Y have the same meaning as defined
above and W represents mesyl, tosyl or benzylsul~onyl
group. This step may preferably be carried out by re-
actin~ the compound of the formula (XII) with mesyl chlo-
ride~ tosyl chloride or benzylsulfonyl chloride in pyridine.
- .
The 4'-0-sulfonylation may be conducted at a temperature
o~ up to 50G. The most preferred sulfonylating agent is
mesyl chloride.
:: 10 The 4'-0-sulfonylated derivative of the formula
(XIII) thus:obtained is then converted to 3',4'-~-epoxy
derivative of the formula (IX) above-mentioned as main
product by treating it with a metal alcoholate. ~he
epoxidatlon reaction may preferably be carried out by
dissolving the compound of the formula (XIII) in a solvent,
for example water, a lower alkanol such as methanol or~
ethanol, diglyme, sulforane, tetrahydrofuran or dimethyl- -
sulfoxide, adding to the solution a metal alcoholate,
- 25
~7~7
usually an alkali or alkaline earth metal alcoholate such
as sodium, potassium, or lithium alcoholate~ part~cularly
a lower alkoxide, for example sodium methoxide or sodium
ethoxide and maintaining the mixture at room temperatures,
usually 15-25C, suitably for 1~3 hours. During the
epoxidation reaction, the hydroxyl-protecting group Y in
the 2"-position is removed because of alkaline condition,
thus the free 2"-OH group is regenerated in the 3',4'-~-
epoxidized derivative of the formula (IX).
3',4'-a-Epoxy derlvative corresponding to the 3',
4'-~-epoxy derivative of the formula (IX) may be derived
from 3'-O-tosyl derivative corresponding to the 4'-O-
sulfonylated derivative of the formula txIII) above, i.e.
the compound of the formula (XIII), but wherein W is
hydrogen and X is tosyl group in the same manner as that
of the 3',4'-epoxidation step as above-mentioned, i.e.
by treating with an alkali-metal~alcoholate such as sodium
methoxide, details of which is given in DT-OS No.2,555,479.
A diagramatic reaction scheme is given below to
show -the preparation of 3',4'-dideoxykanamycin B-starting
from kanamycin B via a new intermediate, 3',4'-~-epoxy ~- -
derivative of~the formula (IX), which is treated according
to the processes of this invention.
: .
.
:- '
.~
- 26
.: :
1~7165~t7
Kanamycin B
Protection of five NH2 groups
: ~ with -COOR group
CH2~HCOOR NHCOOR
~ ~ HCOOR
HO~
HCOOR
.
;~ /
: O
:: . HOC~2 ¦ /
OH
,' ~
: .
Protection of 4"- and ;6"-
:~ 1 OH groups with group Z `~
. . .
- C~ COOR j ~HCOOR
~~ /I~COOR
E~
~HCOOR
OCH2 ¦ / '
~ / ~1~' ' /
\ 1~ NHCOOR)~ .
~' Oy,~
OH
-- 27
, . . . . . . .. . . . .. . .
.
67
Protection of 2" and 3'-
. OH groups with acyl groups
. ~ Y and X, respectively
CH2NHCOOR ~HCOOR
~ ~ ~ NHCOOR -
H,~ ~ O ~
:~ Z~o ~
. OY
¦ 4'-O-Sulfonylation
I (Introduction of W group)
CH2~HCOOR ~HCOOR
~ ~ NXCOOR
'~ Wl\~L_~ '--`~V/~ ~ '
~ COOR OCH2
/~o
HCOOR
. V
OY
.~ 3',4'-Epdxidation with
1 .
~ an alcoholate :
CH2NHCOOR NHCOOR
~ ~ NHCOOR
~ ~ o _ \\~ ,
~HCOOR
O~cH2 / - '`
/ /1--o o
\ ~NHCOOR ~ ~
0~ ' ~' '
OH
- 28
:' '
5~;7
¦ Treatment with a xanthate
(Route A)(Route B)(Route C)
.. `I -- -- 'I , .
C ~ HCOOR ~ R ~H2NHCOOR ~C09R
: ~ ~ r~ r ~ ~COOR
,' ~0~
~-0~
N~COOR / NHCOOR
: OCH2 OCH2
Z/ ~ / Z/~O
', , \~ \o~
~ OII
, Treatment with
. hydrazine or Raney nickel
(Route C) ,
'~ . .
Treatment
. Hydrogenation iRemoval of the NH2-and OH-protections with an acid
.~
. (Route D) (Route A)(Route C) (Route B)
)
CH2NHCOOR ~HCOOR C~2NH2 NH2
~ ~ ~ NHCOOR f ~ ~ 2
; ~ ~ ~ 2
NHCOOR
Z~
OH OH
.: - 29 -
.~
~7~5~7
\ Removal of the
\ NH2- and OH-protections /Hydrogenation
\(Route D) / (RouteA)(Route B)(Route C)
,l
CH2NH2
o ~ ~ ~H2
'' ' \~/' ' ~~V~
~H2 / : . -
.~ / ,
. /
O
HOCH 2
~ ro/
~ ¦~ NH2 A/
HO ~
OH
~ .- . .
Route A = The first aspect process of this invention
Route B = The second aspect process of this in~ention
. Route C = The third aspect proce~s of this invention
Route D = An alternative of the flrst or third aspect
process of this invention
,
. ~ ., .
. - 3
;5~7
PREFERRED EMBODIMENTS OF THE INVENTION:
This invention is further illustrated by way of
Examples which include overall steps starting from
kanamycin B and leading to the final product, 3',4'-
dideoxykanamycin B, through several routes according
to this invention.
Example 1
(1) Preparation of penta-N-ethoxycarbonylkanamycin B
Penta-N-ethoxycarbonylkanamycin B was prepared
from kanamycin B free base by the method described in
Example 1 of British Patent No.1,349,302.
(2) Prepara~ion of 2",3'-di-0-benzoyl-penta-N-
ethoxycarbonyl-4",6"-0-cyclohexylidene-kanamycin B
Penta-N-ethoxycarbonylkanamycin B (10 g) was
suspended in dimethylformamide (70~1 ), to which
was added p-toluene sulfonic acid until the pH of
the suspension was lowered below 3.0 and then added
cyclohexanedimethylketal (10 ml). The mixture was
maintained at 25C under stirrlng for 18 hours. The
completion of the reaction was confirmed by thin layer
chromatography using silica gel (made by Merck) as
stationary phase~ and chloroform-methanol (10:1 by
volume) as developer and the resulting reaction mix-
ture was neutralized with triethylamine. The neu-
tralized liquid was concentrated under vacuum to
obtain a residual liquid of 25 ml which was then dis-
solved in p~ridine (150 ml). After cooling the
solution to a temperature of 0~5C, benzoyl chloride
(3.9 ml) was added thereto and the mixture was kept to
cause reaction for 3 hours. The completion of reaction
- 31
~L~7~i5f;7
was con~irmed by thin layer chromatography. Water
(5 ml~ was added to the resulting mixture and the
mixture was stirred at room temperature for 30
minutes, concentrated and poured into water (200 ml)
`~ to form precipitate which was recovered by filtration.
Yield 12.7 g (95%). After the purification by a
conventional silica-gel chromatography, the titled
compound had the following physical properties:
~]D + 76.6 (c=l~ pyridine); mp. 233_235C.
Elementary analysis.
Found: C ~5.98; H 6.44; N 5.60%
Calculated for Cs3H73Ns22:
; C 5~.22, H 6.51; N 6.19%
(3) Preparation of 2",3'-di-0-benzoyl-penta-N-
ethoxycarbonyl-4 1l, 6"-0-cyclohexylidene-4'-0-mesyl-
kanamycin B
~ ~2",3'-di-0-benzoyl-penta-N-ethoxycarbonyl-4",
; 6"-0-cyclohexylidene-kanamycin B (5g) was dissolved
in pyridine (100 ml), to which was added mesyl chloride
(1.4 ml) and the mixture was maintained at 40C under
stirring for 1.5 hours. After the mixture was cooled
to room temperature, water (5 ml) was added to the
mixture to decompose the excess mesyl chloride and
the mixture was concentrated. To the concentrate was~
added water (200 ml) to precipitate the titled compound3
which was recovered by filtration. Yield 5~.0g (9~%);
[a]~ 103.6 (c=l.0, pyridine); mp. 176~179C.
Elementary analysis:
Found: C 53.28; H 6.25; N 5.41; S 2.95%
Calculated for Cs4H7sNsO2~S:
- 32
. .
i
','. ,
7~
C 53.59; H 6.25; N 5.79; S 2.65%
(4) Preparation of 3',4'-~~epoxy-penta-N-ethoxy-
carbonyl-4",6"-0-cyclohexylidene-kanamycin B
2",3'-Di-0-benzoyl-penta-N-ethoxycarbonyl-
4",6"-0-cyclohexylidene-4'-mesyl-kanamycin B (5 g)
was dissolved in methanol (100 ml), to which was
added sodium methylate (2.2 g). The mixture was
maintained at room temperature under stirring for
2 hours. After the completion of reaction was con-
firmed by thin layer chromatography using silica gel
as stationary phase and carbon tetrachloride-acetoné
(1:1 by volume) as de~eloper, the reaction mixture
was ice-cooled~ neutralized with concentrated hydro-
chloric acid (1.25 ml) and concentrated. To the
neutralized concentrate was added water (100 ml) to
precipitate the titled compound which was recovered by
filtration. Yield 3.5 g (95%); ~3D + 37.8 (c=l.0,
pyridine), mp. 254~258C (decomposition with ~oaming).
Elementary analysis:
Found: C 51.86; H 6.89; N 7.58; 0 33.67%
Calculated ~or C3sH63NsOIs:
C 51.69; H 7.02; N 7.73; 0 33.55%
(5) Preparat]on of 3',4'-dideoxy-3'-eno-penta-N-
ethoxycarbonyl~4",6l'-0-cyclohexylidene-kanamycin B
3',4'-~-Epoxy-penta-N-ethoxycarbonyl-411,6"-0-
cyclohexylidene-kanamycin B (800 mg) was suspended
in n-butanol (40 ml), to which was then added potassium
n-butylxanthate (1.7 g) and the reaction was conducted
at 80C for 4 hours. After the completion of reaction
was confirmed by silica-gel thin layer chromatography
- 33
~7~i67
. .
using carbon tetrachloride-acetone (l:1 by volume)
as developer, the mixture was cooled and washed with
water (40 ml x 2) and the resulting butanol layer
was concentrated to dryness. Yield 900 mg. This was
confirmed by silica-gel thin layer chromatography to
be a mixture of 3',4'-dideoxy-3'-eno-penta-N-ethoxy-
carbonyl-4",6"-cyclohexylidene-kanamycin B and 3',4'-
episulfido~penta-N-ethoxycarbonyl-4",6"-0-cyclohexyli-
dene-kanamycin B in approximately 1:1 proportion.
The mixture was sub~ected to silica-gel thin
layer chromatography using carbon tetrachloride-acetone
(5:1 by volume) as developer, affording 3'~4'-dideoxy-
3'-eno-penta-N-ethoxycarbonyl-4",6"-cyclohexylidene-
kanamycin B with [~]2D of + 24.7 (c=l.0, methanol) and
3',4'-episulfido-penta-N-ethoxycarbonyi-4",6"-0-cyclo-
2S
hexylidene-kanamycin B with ~]D ~ ~ 10.8 (c=l.0,
H20) and melting polnt of 250-260C (with decomposi-
tion), separately.
Elementary analysis o`f the latter compound:
; Found: C 50.41; H 6.95; N 7.45; S 3.48%
Calculated for C3sHs3NsOLsS:
C 50.79; H 6.90; N 7.60; S 3.48%
. (6) Preparation of 3',4'-dideoxy-3'-eno-kanamycin B
3 "4 t -Dideoxy-3'-eno-penta-N-ethoxycarbonyl-
4",6"-0-cyclohexylidene-kanamycin B (475 mg) was
dissolved in methanol (5 ml)~ to which was added an
amount of l N HCl sufficient to adjust the pH value
of the solution to 2Ø The solution was heated at
50C for 30 minutes and, after adding water (5 ml)
and then barium hydroxide octahydrate (1.4 g), further
, ' :
, ' , ' ' , ' ' , ' . ' ' ' :
~76~
heated to distill off the methanol and the remaining
mixture was refluxed for 8 hours and then cooled.
Carbon dioxide gas was passed through,the
cooled mixture and barium carbonate thus formed was
removed by filtration. Purification through a column
of Amberlite CG-50 tNH4 f'orm) gave the titled com-
pound. Yield 560 mg (2~%).
- Elementary analysis:
Found: C 47,85; H 7.95; N 15.40%
Calculated for ClsH3sNs 8
C 48.11; H 7.80; N 15.59%
(7) Preparation of 3',4' dideoxykanamycin B
3'4'-Dideoxy-3'-eno-kanamycin B tl20 mg) was
dissolved in water (4 ml), to which Raney nicXel (0.2
~ ~ ml) was added. Hydrogen was passed through the solution
i for 2 hours under atmospheric conditions of temperature
and pressure. After the catalyst used was filtered off,
the filtrate was concentrated to dryness. Yield 108 mg
t95%)
Example 2
(1) Preparation of penta-N-t-butoxycarbonyl-kanamycin B
,~ ~ Kanamycin B (10 g) was added to a mixture of
water (34 ml), triethylamine t24 ml)~and dimethyl-~
formamide (48 ml). Then, t-butyl-S (4,6-dimethyl- ~
~, pyrimidin-2~yl)-thiol-carbonate t40 g) was added to the
mixture at room temperature and the mixture was stirred
at that temperature for 18 hours. Addition of water
t150 ml) to the mixture formed crystals which were re- -
covered by filtration and washed thoroughly wîth an
aqueous saturated solution of ethyl acetate. Yield 20
- 35 -
.
S~
g (100%). mp.229 234C (decomposition with foaming).
Elementary analysis:
Found: C 52.61~ H 7.86; N 6.93%
r Calculated for C43H77N5020:
C 52.47; H 7.90, N 7.12%
(2) Preparation of 3',4'-~-epoxy-penta-N-t-butoxy-
carbonyl-4",6"-O~cyclohexylidene-kanamycin B
Penta-N-t-butoxykanamycin B (10 g) was treated
in the same ways as those described in Example 1 (2),
(3) and ( 11 ) above, yielding the titled compound. Yield
80%, [a~2D + 27(c=l.0; pyridine). mp. 232~234C
~ (decomposition with foamlng).
;~ (3) Preparation o~ 3',4'-episulfido-penta-N~t-butoxy-
carbony1-4i',6"-0-cyclohexylidene-kanamycin B
. : .
3l~4t-~-Epoxy-penta-N-t-butoxyc~*~ny~ r6
hexylidene-kanamycin B (10 g) was suspended in n-butanol
~100 ml), to which was added potassium n-butylxanthate
(9.5 g) and the reaction was conducted at 90C for 2
hours. APter the reaction was completed, the mixture
~ ~ 20 was cooled and washed twice with 100 ml portions of
- water and the butanol layer separated was concentrated
to dryness, affording a mixture comprising 3',4'-
.
episul~ido-penta-N-t-butoxycarbonyl-4",6"-cyclohexylidene-
- kanamycin B and 3',4'~dideoxy-3'-eno-penta-N-t-butoxy-
carbonyl-4'76"-cyclohexylidene kanamycin B. Yield 11 g.~ -
The crude product was subjected to silica gel chromato-
graphy using chloroform-methanol (50:1 by volume) as
developer, to isolate 3',4'-episul~ido-penta-N-t-butoxy-
carbonyl-4",6"-cyclohexylidene~kanamycin B. Yield 3.9 g
(35%)- [~]D + 23 (c= 1.0, pyridine). mp. 235~238C
.
. .
6~;6~7
(decomposition with foaming).
Elementary analysis:
Found: C 55.10, H 7.94; N 6.31; S 3.30%
Calculated for C~sHs3NslsS:
C 55.39; H 7.89; N 6.59; S 3.02%
(43 Preparation of 3',4'-dideoxy-3'-eno-kanamycin B
3',4'-Episulfido-penta-N-t-butoxycarbonyl~4",
- - - - 6"-0-cyclohexylidene-kanamycin B (1.15 g) was dissolved
in methanol tl2 ml), to which was added concentrated
hydroohloric acid (3~ml) and the reaction was conducted
at room temperature ~or 3 hours.
` The reaction mixture was concentrated ta dryness
and the resulting residue was dlssolved in water (18
ml) and the pH of the solution was adjusted to 6.5 by
the addition of lN sodium hydroxide solution (2.5 ml).
The solution was passed through a column of 20 ml of
Amberlite CG-50 (NH4~ form). The aùsorbed column was
washed with water and then O.lN aqueous ammonia and
subsequently eluated with 0.3N aqueous ammonia. The
concentration of the eluate gave the titled compound.
Yleld 194 mg.
(5) Preparation of 3',4'-dideoxykanamycin B
3'4'-Dideoxy-3'-eno-kanamycin B (120 mg) was
dissolved in water (4 ml), to whlch was added Raney
nickel (0.2 ml) and hydrogen was passed through the
; mixture for 2 hours under atmospheric temperature and ~ -
pressure conditions. After the catalyst was filtered
off, the filtrate was concentrated to dryness, giving
the tilted compound. Yield 108 mg (90%).
E~ample 3
- * Trade Mark
- 37 -
'
: .
. . , . : .
.
5~7
Preparation of 3',4'-episulfido-penta-N-ethoxycarbonyl-
4",6"-0-cyclohexylidene-kanamycin B
3',4'~ Epoxy-penta-N-ethoxycarbonyl-4",6"-0-
cyclohexylidene-kanamycin B (lOO mg) which was prepared
by the method described in Example l of DT-OS 2,555,479
was dissolved in pyridine (5 ml), to which was added
potassium ethyl xanthate (lOO mg) and the mixture was
refluxed for l.5 hours and then concentrated to dryness.
A mixture of water and chloroform (2:3 by volume) was
added to the solid residue and the chloroform layer .
was separated, washed three times with 20 ml portions
of water and concentrated to dryness, yielding 70 mg
of a crude product comprising 3',4'-episulfido-penta-
N-ethoxycarbonyl-4",6'1-O-cyclohexylidene-kanamycin B
and 3',4'-dideoxy-3'-eno-penta-N-ethoxycarbonyl-4",6"-
O-cyclohexylidene-kanamycin B.
The isolation of the respective compounds was
carried out by thin layer chromatography in the same
manner as that used in Example 1 (5) above.
Example 4
(1) Preparation of 3',4'-dideoxy-3'-eno-penta-N-
ethoxycarbonyl-4",6"-0-cyclohexylidene-kanamycin B
31,4'-Episulfido-penta-N-ethoxycarbonyl-4",6"-O-
cyclohexylidene-kanamycin B (470 mg) which was prepared
as described in Example 1 (5)(or Example 3(1)) above
was dissolved in methanol (2 ml), to which was added
hydrazine hydrate (0.22 ml) and the mixture was allowed
to stand at room temperature for 2 hours. The reaction
mixture was then concentrated to dryness and treated
with water (20 ml) to form precipitate which was re-
-- 38
~Ct76~i~7
covered by filtration. Yield 362 mg (80%). ~]D +
24.7 (c=l.0, methanol).
Elementary analysis:
Found: C 52.31; H 7.53; N 7.49%
Calculated for C3sH6 sNsOl 8:
C 52.50; H 7.36; N 7.85%
(2) Preparation of 3',4'-dideoxy-3'-eno-kanamycin B
3',4'-Dideoxy-3'-eno-penta-N-Ethoxycarbonyl-4",
6"-cyclohexylidene-kanamycin B (475 mg) was dissolved
in methanol (5 mlj and treated in the same manner as
that described in Example 1 (6)~ affording the titled
compound.
~; (3) Preparation of 31,4'-dideoxykanamycin B
- 3',4'-Dideoxy-3'-eno-kanamycin B was treated
as similar as in Example 1 (7), affording the titled
compound.
Example_5
(1) Preparation of 3',4'-dideoxy-3'-eno-penta-N-t-
butoxy-4",6"-0-cyclohexyIidene-kanamycin B
3 t ~ 4'-Episulfido-penta-N-t-butoxycarbonyl-4",6"-
0-cyclohexylidene-kanamycin B (585 mg) which was prepared
as in Example 2 (3) was dissolved in me~hanol (7 m~l), to
which was added Raney nickel (R-100)(500 mg) and~the
mixture was stirred at room temperature (20C) for 2
hours. After the Raney nickel was removed by filtration,
` ~ the filtrate was concentrated to dryness, affording the
titled compound. Yield 450 mg (80%3.
(2) Preparation of 3',4t-dideoxykanamycin B
3 "4 t -Dideoxy-3'-eno-penta-N t-butoxy-4",6 It _
0-cyclohexylidene-kanamycin B (450 mg) was treated as
.~ .
.
~ ~ ' ' ,
6516~7
similar as in Example 1 (6) and (7), affording the titled
compound. Yield 90%.
Example 6
(1) Preparation of 3',4'-~-epoxy-penta-N-t-butoxycarbonyl-
4",6"-0-cyclohexylidene 2"-0-benzoyl-kanamycin B
~ 3',4'-~-Epoxy-penta-N-t-butoxycarbonyl-4",6"-0-
; cyclohexylidene-kanamycin B (2.0 g) was dissolved in
dry pyridine (40 ml), to which was added benzoyl chloride
(o.8 ml) under ice-cooling and the mixture was allowed to
stand for reaction at 5C for 30 minutes. Then~ water
(2 ml) was added to the reactlon mixture and the mlxture
was concentrated to give a syrup which was then poured
into water (20 ml) to form precipitate. The precipitate
~was recovered by filtration and dried to yield the titled
compound. Yield 2.16 g (98.3%).
t2) Preparation of 4~-deoxy-4~-iodo-penta-N-t-but
. . .
~ ~ carbonyl-4",6!'-0-cyclohexylidene-2"-0-benzoyI-kanamycin B
;: .
' ~ 3',4'-~epoxy-penta-N-t-butoxycarbonyl-4",6"-0-
cyclohexylidene-2"-0-benzoyI-kanamycin B (2.1 g~ was
. .~ . .
. 20 dissol~ed in acetone (60 ml),~to which were added sodium
iodide (1.4 g), sodium acetate (80 mg) and glacial acetic
acid (1.4 ml3 and the resulting mixture was refluxed
; for about 8 hours.
After the completion of the reaction, the mixture
was cooled to deposit crystals which were recovered~by
filtration. Yield 2.25 g (94%). mp. 171_176C (with
decomposition).
Elementary analysis:
Found: C 52.81; H 7.11; N 5.31; I 10.39%
Calculated for C4 3 H7 6 NsOIgI:
.
.
..
. :
.
.~' . . .
7~
C 52.62; H 6.94; N 5.48; 1 9.93%
(3) Preparation of 3',4'-dideoxy-3'-eno-penta-N-t-butoXy-
carbonyl-4",6"-0-cyclohexylidene-2"-0-benzoyl-kanamycin B
~ '-Deoxy-4'-iodo-penta-N-t-butoxycarbonyl-4",6"-
O~cyclohexylidene-2"-0-benzoyl-kanamycin B (452 mg) was
dissolved in dry pyridine (9 ml), to which was added
benzylsulfonyl chloride (305 mg) under cooling to 0~~5C
for about 30 minutes.
After the completion of the reaction, methanol
(0.18 ml) was added to the reaction mixture which was
then heated to 90C for 50 minutes, cooled to room tem
perature. The mixture was concentrated to a syrup, to
which water (10 ml) was added to deposit crystals. The
crystals were recovered by filtration and washed with
water to obtain the titled compound in the form of
a wet cake.
Identification of the compound thus obtained
was made by silica-gel thin layer chromatography using
carbon tetrachloride-acetone (4:1 by volume) as developer.
.
(4) Preparation of 3',4'-dideoxy-3'-eno-penta-N-t-
butoxycarbonyl-4",6"-0-cyclohexylidene-kanamycin B
The wet cake of the compound obtained in the
step (3) above was dissolved in methanol (20 ml), to
which sodium methylate was added to adjust the pH to
9.0~10.0 and the mixture was stirred at room temperature
for 30 minutes, neutralized w~th lN HC1 and concentrated
to a syrup. Addition of water to the syrup formed a
precipitate which was recovered by filtration, washed
with water and dried to afford the titled compound.
Yield 3~0 mg (100%).
- 41
