Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
This invention is concerned with cephalosporin
compounds possessing valuable antibiotic properties.
The cephalosporin compounds in this specification
are named with reference to "cepham" after J.Amer.Chem.
S ., 1962, 84, 3400, the term "cephem" referring to the
basic cepham structure with one double bond.
Cephalosporin antibiotics are widely used in the
treatment of diseases caused by pathogenic bacteria in
human beings and animals, and are especially useful in
the treatment of diseases caused by bacteria which are
resistant to other antibiotics such as penicillin com-
pounds, and in the treatment of penicillin-sensitive
patients. In many instances it is desirable to employ a
cephalosporin antibiotic which e~hibits activity against
both gram-positive and gram-negative microorganisms, and
a significant amount of research has been directed to the
development of various types of broad spectrum cephalosporin
an~ibiokics.
Thus, for example, in our British Patent Specifica-
20 tion No. 1,399,0867 we describe a novel class of cephalo-
sporin antibioticscontaining a 7~ -etherified oxyimino)-
acylamido group, the oxyimino group having the ~y~ config-
uration. T~is class of antibiotic compounds is character-
ised by high antibacterial activity against a range of
., -. :~ . . ,
'
. ~ :
~ ~ 3~
gram-positive and gram-~egative organisms coupled with
particularly high stability to ~-lactamases produced by
various gram-negative organisms.
The discovery of this class of compounds has
stimulated further research in the same area in attempts
to find compounds which have improved properties, for
example against particular classes of organisms especially
gram-negative organisms.
In our British Patent Specification No. 1,496,757,
we describe cephalosporin antibiotics containing a 7~-
acylamido group of the formula
R.C.CO.NEI-
N RA (A)
O.(CH2)m C (CH2) COOH
R
(wherein R is a thienyl or furyl group; RA and RB may
vary widely and may, for example, be Cl ~ alkyl groups or
together with the carbon atom to which they are attached
form a C3 7 cycloalkylidene group, and m and n are each O
2~ or 1 such that the sum of m and n is O or 1), thecompounds being syn isomers or mixtures of syn and anti
isomers containing at least 90% of the syn isomer. The
3-position of the cephalosporin molecule may be unsub- -
stituted or may contain one of a wide variety of possible
substituents These compounds have been found to have
particularly good activity against gram-negative organisms.
Other compounds of similar structure have been
developed from these compounds in further attempts to find
antibiotics having improved broad spectrum antibiotic
~.~ 3 i~ ~
activity and/or high activity against gram-negative
organisms. Such developments have involved variations in
not only the 7~-acylamido group of formula (A) but
also the introduction of particular groups in the 3-
position o~ the cephalosporin molecule~
Thus, for example, South African Patent Specifica-
tion 78/1870 discloses cephalosporin antibiotics wherein
the 7~-acylamido side chain is inter alia a 2-(2-amino-
thiazol-4-yl)-2-(optionally substituted alkoxyimino)-
acetamido group and the 3-position may be substituted, for
example, by the group -CH2Y in which Y represents the
residue of a nucleophile. The Specification contains,
among numerous other examples, references to compounds in
which the above-mentioned optionally substituted alkoxy-
imino group is a carboxyalkoxyimino or carboxycycloalkoxy-
imino group. With regard to the 3-position, mono- and
di-alkylaminomethyl substituents arereferred to, among
numerous other possibilities. South African Patent
Specification 78/2168 discloses in broad terms sulphoxide
compounds corresponding to the sulphides described in the
last-mentioned Specification.
~ urthermore, Belgian Patent Specification No.
836,813 describes cephalosporin compounds wherein the
group R in formula (A) above may be replaced by, ~or
example, 2-aminothia2O1-4 yl, and the oxyimino group is a
hydroxyimino or blocked hydroxyimino group, e4g, a
methoxyimino group. In such compounds, the 3-position of
the cephalosporin molecule is substituted by a methyl
group which may itself be optionally substituted by any of
-- 4 --
~ 1 3~
a large number of residues of nucleophilic compounds
therein described. N-Alkylaminomethyl groups are
mentioned as possible substituents in the 3-position but
only mono- and di-alkylaminomethyl groups are specifically
identified. In the above-mentioned Specification no
antibiotic activity is ascribed to such compounds which
are only mentioned as intermediates for the preparation
of antibiotics described in that Specification.
- 5 -
~ ~ 3~
We have now discovered that by an appropriate
selection of a small number of particular groups at the
7~-position in combination with a trialkylammoniomethyl
group at the 3-position, cephalosporin compounds having
particularly advantageous activity (described in more
detail below) against a wide range of commonly encountered
pathogenic organisms may be obtained.
~ le present invention provides cephalosporin anti-
biotics of the general formula:
NH2
S N , , 1
C.CO.NH - ~ S ~ R
~ 32 (I)
N IR O ~ N ~ CH2l-R
O.C.COOH I a 3
Ib COO R
(wherein R and Rb, which may be the same or different,
each represent a Cl 4 alkyl group (preferably a straight
chain alkyl group, i.e. a methyl, ethyl, n-propyl or n-
butyl group and particularly a methyl or ethyl group) or
Ra and Rb together with the carbon atom to which they are
attached form a C3 7 cycloalkylidene group, preferably a
C3 5 cycloalkylidene group; and R , R and R , which may
be the same or different, each represents a Cl 4 alkyl
group, e.g~ a methyl group)and non-toxic salts and non-
toxic metabolically labile esters thereof.
The compounds according to the invention are synisomers. The syn isomeric form is defined by the
configuration of the group
. . .
'
.
- O.C.COOH
Ib
with respect to the carboxamido group. In this Specifi-
cation the ~y~ configuration is denoted structurally as
NH2
C.CO~NH
N Ra
O.C.COOH
Ib
It will be understood that since the compounds
according to the invention are geometric isomers, some
admixture with the corresponding anti isomer may occur.
The invention also includes within its scope the
solvates (especially the hydrates) of the compounds of
formula (I). It also includes within its scope salts of
esters of compounds of formula (I).
The compounds according to the present invention
may exist in tautomeric forms (for example in respect of
the 2-aminothiazolyl group) and it will be understood that
such tautomeric forms, e.g. the 2-iminothiazolinyl form,
are included within the scope of the invention~ Moreover,
the compounds of formula (I) depicted above may also exist
in alternative zwitterionic forms~ for example wherein the
4~carboxyl group is protonated and the carboxyl group in
the 7-side chain is deprotonated. These alternative
forms, as well as mixtures of zwitterionic forms1 are
~ 6~
included within the scope of the present invention.
It will also be appreciated that when R and R in
the above formula represent different Cl 4 alkyl groups,
the carbon atom to which they are attached will comprise
a centre of asymmetry. A centre of asymmetry will also
be present when Rl, R2 and R3 all represent different
alkyl groups. Such compounds are diastereoisomeric and
the present invention embraces individual diastereoisomers
of these compounds as well as mixtures thereof.
The compounds according to the invention exhibit
broad spectrum antibiotic activity. Against gram-nega-
tive organisms the activity is unusNally high. This high
activity extends to many ~-lactamase-producing gram-
negative strainsO The compounds also possess high
stability to ~-lactamases produced by a range of gram-
negative and gram-positive organisms.
Compounds according to the invention have been
found to exhibit unusually high activity against strains
of Pseudomonas organisms, e.g. strains of Pseudomonas
aeru~inosa as well as high activity against various members
of the Enterobacteriaceae (e.g. strains of Escherichia
c _ , Klebsiella pneumoniae, Salmonella typhimurium9
Shi~ella sonnei, Enterobacter cloacae, Serratia marcescens,
Providence species, Proteus mirabilis, and especialIy
indole-positive Proteus organisms such as Proteus vul~aris
and Proteus morganii) and strains of Haemophilus
influenzae.
~ .
The antibiotic properties of the compounds accord-
ing to the invention compare very favourably with those of
3~
the aminoglycosides such as amikacin or gentamicin. In
particular, this applies to their activity against strains
of various Pseudomonas organisms which are not susceptible
to the majority of existing commercially available anti-
biotic compounds. Unlike the aminoglycosides, cephalo-
sporin antibiotics normally exhibit low toxicity in man.
The use of aminoglycosides in human therapy tends to be
limited or complicated by the relatively high toxicity
of these antibiotics. The cephalosporin antibiotics of
the present invention thus possess potentially great
advantages over the aminoglycosides.
Non-toxic salt derivatives which may be formed by
reaction of either or both of the carboxyl groups present
in the compounds of general formula (I) include inorganic
base salts such as alkali metal salts (e.g. sodium and
potassium salts) and alkaline earth metal salts (e.g.
calcium salts); amino acid salts (e.g. lysine and
arginine salts); organic base salts (e.g. procaine,
phenylethylbenzylamine, dibenzylethylenediamine, ethanol-
amine, diethanolamine and N-methylglycosamine salts).
Other non-toxic salt derivatives include acid addition
saltsg e.g. fonmed with hydrochloric, hydrobromic,
sulphuric, nitric, phosphoric, formic and trifluoroacetic
acids. The salts may also be in the form of resinates
fnrmed with, for example, a polystyrene resin or cross-
linked polystyrene divinylbenzene copolymer resin con-
taining amino or quaternary amino groups or sulphonic
acid groupsy or with a resin containin~ carboxyl groups,
e.g. a polyacrylic acid resin. Soluble base salts (e.g.
~ ~ 3~
alkali rnetal salts such as the sodium salt) of compounds '
of formula ~I~ may be used in therapeutic applications
because of the rapid distribution of such salts in the
body upon administration. Where, however, insoluble
salts of compounds (I) are desired in a particular appli-
cation, e.g. for use in depot preparations, such salts
may be formed in conventional manner, for example with
appropriate organic amines.
These and other salt derivatives such as the salts
with toluene-p-sulp'honic and methanesulphonic acids may
be employed as intermediates in the preparation and/or
purification of the present compounds of formula (I), for
example in the processes described below~
Non-toxic metabolically labile ester derivatives
which may be formed by esterification of either or both
car'boxyl groups in the parent compound of formula (I)
include acyloxyalkyl esters e~g. lower alkanoyloxy-methyl
or -ethyl esters such as acetoxy-methyl or -ethyl or
pivaloyloxymet'hyl esters. In addition to the above ester
derivatives 9 the present invention includes within its
scope compounds of formula (I) in the form of other
physiologically acceptable equivalents, i.e. physiologic-
ally acceptable compounds which, like the metabolically
labile esters are converted in vivo into the parent anti-
biotic compound of formula (I).
Preferred compounds according to the presentinvention include those compounds of formula (I) wherein
Rl, R and R all represent methyl groups. Preference
is also expressed for those compounds wherein R and R~
both represent methyl groups or together with the carbon
' ' ' , ' '
- 10 -
~1~3~B
atom to which they are attached form a cyclobutylidene
group. (6R, 7R)-7-~(Z)-2-(2-Aminothiazol-4-yl)-2-(1-
carboxycyclobut-l-oxyimino)acetamido] 3-trimethylammonio-
methyl-ceph-3-em-4-carboxylate ~nd its non-toxic salts
and non-toxic metabolically labile esters are particularly
preferred compounds according to the present invention.
Other preferred compounds include (6R, 7R)-7-[(Z)-2-(2-
aminothiazol 4-yl)-2-(2-carboxyprop-2-oxyimino)acetamido~-
3-trimethylammoniomethyl-ceph-3-em-4-carbOxylate acid and
its non-toxic salts and non-toxic metabolically labile
esters.
Other compounds according to the present invention
inclùde those for example wherein the groups Ra, Rb, Rl,
R2 and R3 in formula (I) are as follows:-
Ra - Rb - R3
a) Alkyl ~roups
-CH3 2 5 CH3 CH3 CH3
. -C2H5 C2H5 CH3 CH3 CH3
-CH3 -CH3 C2H5 CH3 CH3
-CH3 2 5 C2H5 CH3 CH3
C2H5 C2H5 C2H5 CH3 CH3
-CH3 -CH3 C2H5 C2H5 CH3
-CH3 2 5 C2H5 C2H5 CH3
2H5 -C2H5 C2H5 C2H5 CH3
-CH3 -CH3 C2H5 C2H5 C2H5
-CH3 -C2H5 C2H5 C2H5 C2H5
2 5 2 5 C2H5 C2H5 C2H
- r b . _ - R3
R - ~ - R R
b) Cycloalkylidene grou*s
cyclopropylidene -CH3 -CH3 -CH3
cyclopentylidene _CH3 CH3 -CH3
cyclopropylidene 2 5 -CH3 -CH3
cyclobutylidene 2 5 -CH3 -CH3
cyclopentylidene 2H5 -CH3 -CH3
cyclopropylidene 2H5 -C2H5 -CH3
cyclobutylidene 2 5 -C2H5 -CH3
cyclopentylidene 2H5 -C2H5 -CH3
cyclopropylidene 2 5 -C2H5 -C2H5
cyclobutylidene C2H5 -C2H5 -C2H5
cyclopentylidene -C2H5 -C2H5 -C2H5
The compounds of formula (I) may be used for treat-
ing a variety of diseases caused by pathogenic bacteria in
human beings and animals, such as respiratory tract
infections and urinary tract infections.
According to another embodiment of the invention we
provide a process for the preparation of an antibiotic
compound of general formula (I) as hereinbefore defined or
a non-toxic salt or non-toxic metabolically labile ester
thereof which comprises (A) acylating a compound of the
formula
H H
2 ~ B ~ R
~ CH2N - R2 (II)
coo~3 R3
[wherein R , R and R are as defined above; B is ,S or
~S ~3 0 (a- or ~-); and the dotted line bridging the 2-,
3- and 4-positions indicates that the compound is a ceph-
2-em or ceph-3-em compound] or a salt, e.g. an acid addi-
tion salt (formed with, for example, a mineral acid such
as hydrochloric, hydrobromic, sulphuric, nitric or phos-
phoric acid or an organic acid such as methanesulphonic
or toluene-p-sulphonic acid) or an N~Silyl derivative
thereof, or a corresponding compo~nd having a group of
formula - CoOR4 at the 4-position [where R4 is a hydrogen
atom or a carboxyl blocking group, e.g. the residue of an
es~er-forming aliphatic or araliphatic alcohol or an
ester-forming phenol, silanol or stannanol (the said
alcohol, phenol, silanol or stannanol preferably
~3~6~
containing 1-20 carbon atoms)] and having an associated anion A~
such as a halide, e.g. chloride or bromide, or trifluoroacetate
anion, with an acid of formula
S ~ N
C.COOH
R lIII)
O.C.COOR
Rb
(wherein Ra and Rb are as hereinbefore defined; R5 represents a
carboxyl blocking group, e.g. as described for R4; and R6 is an
amino or protected amino group) or with an acylating agent
corresponding theret~; (B) reacting a compound of formula
R6
S ~ N H H
\ / C.CO.NH ~ L~ ~
N R O ~ C~2X
O.C.COOR a 1 7 (IV)
Rb COOR
(wherein Ra, Rb, R6, ~ and the dotted line are as hereinbefore
defined; R7 and R7a may independently represent hydrogen or a
carboxyl blocking group; and X is a replaceable residue of a
nucleophile (i.e. a leaving group), e.g. an acyloxy group such as
a dichloroacetoxy group or a halogen atom such as
-13-
,
_ lL _
chlorine7 bromine or iodine) or a salt thereof, with a
tertiary amine of the formula
IRl 2
N - R (V)
R3
(wherein Rl, R2 and R are as defined above);
or (C) alkylating a compound of the formula
R
~ H H
\ 7, ~ CH2N
O.C.COOR COOR R
Ib (VI)
(wherein Ra, Rb, Rl, R2, R6, B and the dotted line are as
hereinbefore defined; and R7 and R7a both represent car-
boxyl blocking groups) with an alkylating agent serving to
form a group of formula
Rl
-CH N6~- R
2R3
at the 3-position;
whereafter, if necessary and!or desired in each instance,
any of the following reactions, in any appropriate sequence,
are carried out:-
i) conversion of a ~ -isomer into the desired ~ -
isomerS
ii) reduction of a compound wherein B is ~S-~ O to
~ ~ 3
form a compound wherein ~ is ~S~
iii) conversion o a carboxyl group into a non-toxic
salt or non-toxic metabolically labile ester
~unction, and
iv) removal of any carboxyl blocking and/or N-
protecting groups.
In the above-described process (A), the starting
material of formula (II) is preEerably a compound
wherein the dotted line represents a ceph-3-em
compound.
Acylating agents ~hich may be employed in the
preparation of compounds of formula (I) include acid
halides, particularly acid chlorides or bromides. Such
acylating agents may be prepared by reacting an acid (III)
or a salt thereof with a halogenating agent e.g. phos-
phorus pentachloride, thionyl chloride or oxalyl chloride.
Acylations employing acid halides may be effected
in aqueous and non-aqueous reaction media, conveniently
at temperatures of from -50 to ~50Ct preferably -20 to
+30~C, if desired in the presence of an acid binding
agent. Sui-table reaction media include aqueous ketones
such as aqueous acetone, esters such as ethyl acetate,
halogenated hydrocarbons su~h as methylene chloride,
amides such as dimethylacetamide, nitriles such as
acetonitrile, or mixtures of two or more such solvents.
Suitable acid binding agents include tertiary amines (e.g.
triethylamine or dimethylaniline~, inorganic bases (e~g~
calcium carbonate or sodium bicarbonate), and oxiranes
such as lower 1,2-alkylene oxides (e.g~ ethylene oxide or
- 16 ~
propylene oxide) which bind hydrogen halide liberat~d in
the acylation reaction.
Acids of formula (III) may themselves be used as
acylating agents in the preparation of compounds of
formula (I). Acylations employing acids (III) are desir-
ably conducted in the presence of a condensing agent, for
example a carbodiimide such as N,N'-dicyclohexylcarbodi-
imide or N-ethyl-N'-~-dimethylaminopropylcarbodiimide; a
carbonyl compound such as carbonyldiimidazole; or an
isoxazolium salt such as N-ethyl-5-phenylisoxazolium
perchlorate.
Acylation may also be effected with other amide-
forming derivatives of acids of formula (III) such as, for
example, an activated ester, a symmetrical anhydride or a
mixed anhydride (e.g. formed with pivalic acid or with a
haloformate, such as a lower alkylhaloformate). Mixed
anhydrides may also be formed with phosphorus acids (for
example phosphoric or phosphorous acids), sulphuric acid
or aliphatic or aromatic sulphonic acids (for example
toluene-p-sulphonic acid). An activated ester may con-
veniently be formed in situ using, for example, l-hydroxy-
benzotriazole in the presence of a condensing ~gent as set
out above. Alternatively, the activated ester may be
preformed.
Acylation reactions involving the free acids or
their above mentioned amide-forming derivatives are
desirably effected in an anhydrous reaction medium, e.g.
methylene chloride, tetrahydrofuran, dimethylformamide or
acetonitrile.
- 17 -
~ 1 3~
If desired, the above acylation reactions may be
carried out in the presence of a catalyst such as 4-di-
methylaminopyridine.
The acids of formula (III) and acylating agents
corresponding thereto may, if desired, be prepared and
employed in the form of their acid addition salts. Thus,
Eor example, acid chlorides may conveniently be employed
as their hydrochloride salts, and acid bromides as their
hydrobromide salts.
The amine compound of formula (V) ~ay act as a
nucleophile to displace a wide variety of substituents X
from the cephalosporin of formula (IV). To some extent
the facility of the displacement is related to the PKa
of the acid HX from which the substituent is derived.
Thus atoms or groups X derived from strong acids tend, in
general, to be more easily displaced than atoms or groups
derived from weaker acids. The facility of the dis-
placement is also related 9 to some exten-t, to the precise
identities of the alkyl groups in the compound of formula
(V).
The displacement of X by the amine of formula (V)
may conveniently be effected by maintaining the reactants
in solution or suspensionO The reaction is advantageously
effected using from 1 to 20, preferably 1 to 4, moles of
the amine (V).
Nucleophilic displacement reactions may conven-
iently be carried out on those compounds of formula (IV)
wherein the substituent X is a halogen atom or an acyloxy
group for example as discussed below.
- 18 -
~Y~Y~ 3~
Convenient starting materials for use in the
nucleophilic displacement reaction with the amine of
formula (V) include compounds of formula (IV) in which X
is the residue of a substituted acetic acid e.g. chloro-
acetic acid, dichloroacetic acid and trifluoroacetic
acid.
The substituent X may also be derived from
formic acid7 a haloformic acid such as chloroformic
acid, or a carbamic acid.
When ~sing a compound of formula (IV) in which X
represents a substituted acetoxy group, it is generally
desirable that the group R in formula (IV) should be
a hydrogen atom and that B should represent >S. In
this case, t~e reaction is advantageously e~fected in
an aqueous medium, preferably at a pH of 5 to 8, particu-
larly 5.5 to 7.
The above-described process employing compounds of
formula (IV) in which X is the residue of a substituted
acetic acid may be carried out as described in British
Patent Specification No. 19241,657.
When using compounds of formula (IV) in which X
is an acyloxy group~ the reaction is conveniently
effected at a temperature of -20 to +80C, preferably
0 to ~50C.
- 19
Halo~ens
Compounds o formula (IV) in which X is a chlorine,
bromine or iodine atom can advantageously be used as
starting materials in the nucleophilic displacement reac-
tion with the amine of formula (V). Wh~n using compoundsof formula (IV) in this class, B may represent~ S ~ O and
R7 may represent a carboxyl blocking group. The reaction
is conveniently effected in a non-aqueous medium which
preferably comprises one or more organic solvents,
advantageously ethers, e.g. dioxan or tetrahydrofuran,
esters, e.g. ethyl acetate, amides, e.g. formamide and
N~N-dimethylformamide, and ketones~ e.g. acetone.
Other suitable organic solvents are described in more
detail in Rritish Patent Specification No. 1,326,531.
The reaction medium should be neither extremely acidic
nor extremely basic. In the case of reactions carried
out on compounds of formula (IV) in which R7 and R7a are
carboxyl blocking groups the 3-trialkylammoniomethyl
product will be formed as the corresponding halide
salt which may, if desired, be subjected to one or
more ion exchange reactions to obtain a salt having the
desired anion.
When using compounds of formula (IV) in which X is
a halogen atom as described~above, the reaction is
conveniently effected at a temperature of -10 to ~50C,
'- ~ ' . . - ~ .
.
. .
- 20 -
1131
preferably +10 to +30C.
In process (C) above, the 3-di-C1 4alkylaminomethyl
compound of formula (VI) is advantageously reacted with a
Cl 4 alkylating agent of the formula R Y wherein R is as
defined above and Y is a leaving group such as a halogen
atom (e.g. iodine, chlorine or bromine) or a hydrocarbyl-
sulphonate (e.g. mesylate or tosylate) group, or R3Y
represents dimethyl sulphate. The alkylation reaction is
preferably carried out at a temperature in the range of 0
to 60C, advantageously 20 to 30C. The reaction may be
conveniently effected in an inert solvent such as an ether
e.g. tetrahydrofuran, an amide, e.g. dimethylformamide, or
a halogenated hydrocarbon, e.g. dichloromethane. Alter-
natively, where the alkylating agent is liquid under the
reaction conditions, this agent can itself serve as a
solvent.
The compound of formula (VI) used as starting
material in process (C) may be prepared for example by
reaction of a compound of formula (IV) (as defined above)
with a secondary amine of formula
~Rl
HN (VII)
\ R2
(wherein R and R are as defined above) in an analogous
manner to the nucleophilic displacement reaction described
with respect to process (B). This reaction is preferably
carried out in the presence of an acid scavenging agent.
The amine itself may act as an acid scavenging agent.
The reaction product may be separated from the
1 1 3~
reaction mixture, which may contain, for example, un-
changed cephalosporin starting material and other sub-
stances, by a variety of processes including recrystallisa-
tion, ionophoresis, column chromatography and use of ion-
exchangers (for example by chromatography on ion-exchange
resins~ or macroreticular resins.
L~2-Cephalosporin ester derivatives obtained in
accordance with the process of the invention may be con-
verted into the corresponding L~3-derivative by, for
example, treatment of thel~2-ester with a base such as
pyridine or triethylamine.
A ceph-2-em reaction product may also be oxidised
to yield the corresponding ceph-3-em l-oxide, for e~ample
by reaction with a peracid, e.g. peracetic or m-chloro-
pe~benzoic acid; the resulting sulphoxide may, ifdesired, subsequently be reduced as described hereinafter
to yield the corresponding ceph-3-em sulphide.
Where a compound is obtained in which B is >S -~ O
this may be converted to the corresponding sulphlde by,
for example, reduction of the corresponding acyloxy~
sulphonium or alkoxysulphonium salt prepared in situ by
reaction with e.gO acetyl chloride in the case of an
acetoxysulphonium salt, reduction being effected by, for
example, sodium dithionite or by iodide ion as in a
solution of potassium iodide in a water-miscible solvent
e.g. acetic acid~ acetone, tetrahydrofuran, dioxan, di-
methylformamide or dimethylacetamide. The reaction may
be effected at a temperature of from -20 to ~50C.
Metabolically labile ester derivatives of the
- 22 -
~ ~ 3~
compounds of formula (I~ may be prepar~d by reacting a
compound of formula (I) or a salt or protected derivative
thereof with an appropriate esterifying agent such as an
acyloxyalkyl halide (e.g. iodide) conveniently in an inert
organic solvent such as dimethylformamide or acetone,
followed, where necessary, by removal of any protecting
groups.
Base salts of the compo~mds of formula (I) may be
formed by reacting an acid of Eormula (I) with the
appropriate base. Thus, or example, sodium or potassium
salts may be ~repared using the respective 2-ethyl-
hexanoate or hydrogen carbonate salt. Acid addition
salts may be prepared by reacting a compound of formula
(I) or a metabolically labile ester derivative thereof
with the appropriate acid.
Where a compound of formula (I~ is obtained as a
mixture of isomers, the syn isomer may be obtained by,
for example, conventional methods such as crystallisation
or chromatography.
For use as starting materials for the preparation
of compounds of general formula (I) according to the
invention, compounds of general formula (III) and acid
halides and anhydrides corresponding thereto in their
~_ isomeric form or in the~form of mixtures of the ~X~
isomers and the corresponding anti isomers containing at
least 90% of the syn isomer are pxefera~ly used.
Acids of formula (III) (provided that Ra and Rb
together with the carbon atom to which they are attached
do not form a cyclopropylidene group) may be prepared by
- 23
etherification of a compound of formula
R6
S N
5C.COOR8 (VIII)
N
\ OH
(wherein R6 is as hereinbefore defined and R8 represents
a carbaxyl blocking group), by reaction with a compound of
general formula
Ra
T.C.CooR5 (IX~
Ib
(wherein R , Rb and R5 are as hereinbeore deined and
T is halogen such as chloro, bromo or iodo; sulphate; or
sulphonate such as tosylate), followed by removal of the
carboxyl blocking group R8. Separation of isomers may be
effec~ed either before or aftPr such etherification. The
etherification reaction is generally carried out in the
presence of a base, e.g. potassium carbonate or sodium
hydride, and is preferably conducted in an organic solvent,
for example dimethylsulphoxide, a cyclic ether such as
tetrahydrofuran or dioxan, or an N,N-disubstituted amide
such as dimethylformamide. Under these conditions the
configuration of the oxyimino group is substantially
unchanged by the etherification reaction. The reaction
should be effected in the presence of a base if an acid
addition salt of a compound of Eormula (VIII) is used.
24 -
~13~8
The base should be used in sufficient quantity to neutral-
ise rapidly the acid in question.
Acids of general fonmula (III) may also be prepared
by reaction of a compound of formula
R
,~
S ~ .
CO. COOR8 (X)
(wherein R and R are as hereinbefore defined) with a
compound of formula
Ra
H2N.o.C.CooR5 (XI)
Rb
(wherein-Ra, Rb and R5 are as defined above), followed by
removal of the carboxyl blocking group R8, and where
necessary by the separation of ~y~ and anti iso~ers.
The last-mentioned reaction is particularly applic-
able to the preparation of acids of formula (III) wherein
R and R together with the carbon atom to which they are
attached form a cyclopropylidene group. In this case,
the relevant compounds of formula (XI) may be prepared in
conventional manner, e.g. by means of the synthesis
described in Belgian PatentSpecification No. 866,422 for
the preparation of t-butyl l-amino-oxycyclopropane
carboxylate.
The acids of formula (III) may be converted to the
corresponding acid halides and anhydrides and acid addi- -
tion salts by conventional methods, for example as
described hereinaboveO
'~ '
- 25 -
3L~3~
Where X is a halogen (i.eO chlorine, bromine or
iodine) atom in formula (IV), ceph-3-em starting compounds
may be prepared in conventional manner, e.g. by halogena-
tion of a 7~-protected amino-3-methylceph-3-em-4-carboxylic
5 acid ester l~-oxide, removal of the 7~-protecting group,
acylation of the resulting 7~-amino compound to form the
desired 7~-acylamido group, e.g. in an analogous manner to
process (A) above, followed by reduction of the l~oxide
group later in the sequence. This is described in
British Patent No. 1,326,5310 The corresponding ceph-2-
em compounds may be prepared by the method of ~utch
published Patent Application No. 6,902,013 by reaction of
a 3-methylceph-2-em compound with N-bromosuccinimide to
yield the corresponding 3-bromomethylceph-2-em compound.
Where X in formula (IV) is an acetoxy group, such
starting materials may be prepared for example by acyla-
tion of 7-aminocephalosporanic acid, e.g. in an analogous
manner to process (A) above. Compounds of formula (IV)
in which X represents other acyloxy groups can be
prepared by acylation of the corresponding 3-hydroxy-
methyl compounds which may be prepared for example by
hydrolysis of the appropriate 3-acetoxymethyl compounds,
e.g. as described in British Patent Specifications Nos.
1,474,519 and 1,531,212.
~ e starting materials of formula (II)
are new compounds. These compounds may be
prepared in conventional ~nanner, for example, by
- 26 -
deprotecting a corresponding protected 7~-amino compound
in converltional manner e g. using PC15.
It should be appreciated that in some of the above
transformations it may be necessary to pro~ect any
sensitive groups in the molecule of the compound in
question to avoid undesirable side reactions. For
example, during any of the reaction sequences referred to
above it may be necessary to protect the NH2 group of the
aminothiazolyl moiety, for example by tritylation,
acylation (eOg. chloroacetylation), protonation or other
conventional method. The protecting group may there-
after be removed in any convenient way which does not
cause breakdown of the desired compound, e.g. in the case
of a trityl group by using an optionally halogenated
carboxylic acid, e.g. acetic acid, formic acid, chloro-
acetic acid or trifluoroacetic acid or using a mineral
acid, e.g. hydrochloric acid or mixtures of such acids,
preferably in the presence of a protic solvent such as
water or, in the case of a chloroacetyl group, by treat-
ment with thiourea.
Carboxyl blocking groups used in the preparation ofcompounds of formula (I) or in the preparation of
necessary starting materials are desirably groups which
may readily be split off at a suitable stage in the
reaction se~uence, conveniently at the last stage. It
may, however, be convenient in some instances to employ
non-toxic metabolically labile carboxyl blocking groups
such as acyloxy-methyl or -ethyl groups (eOgO acetoxy-
- 27 -
methyl or -ethyl or pivaloyloxymethyl) and retain these in
the final product to give an appropriate ester derivative
of a compound of formula (I).
Suitable carboxyl blocking groups are well known
in the art, a list of representative blocked carboxyl
groups being included in British Patent No. 1,399,086.
Preferred blocked carboxyl groups include aryl lower
alkoxycarbonyl groups such as ~-methoxybenzyloxycarbonyl,
p-nitrobenzyloxycarbonyl and diphenylmethoxycarbonyl;
lower alkoxycarbonyl groups such as t-butoxycarbonyl; and
lower haloalkoxycarbonyl groups such as 2,2,2-trichloro-
ethoxycarbonyl. Carboxyl blocking group(s) may
subsequently be removed by any of the appropriate methods
disclosed in the literature; thus, for example, acid or
base catalysed hydrolysis is applicable in many cases, as
are enzymically-catalysed hydrolyses.
The following Examples illustrate the invention.
All temperatures are in C. 'Petrol' means petroleum
ether (b.p. 40-60)o
Preparation 1
Et~ (Z)-2-(2-aminoth_azol-4-vl)~2-(hydrox~imino)acetate
To a stirred and ice-cooled solution of ethyl
acetoacetate (292 g) in glacial acetic acid (296 ml) was
added a solution of sodium nitrite (180 g~ in water (~00
ml) at such a rate that the reaction temperature was
maintained below 10C. Stirring and cooling were
continued for about 30 min., when a solution of potassium
chloride (160 g) in water (~00 ml) was added. The result-
ing mixture was stirred for one hour. The lower oily
_~ phase was separa.:ed and the aqueous phase was extracted
with diethyl ether. The extract was combined with the
- 28 - 1 ~ 3~
oil, washed successlvely with wate~ and saturated brine7
drie~, ~nd evaporated, The residual oil, which solidified
on standing, was washed with petrol and dried ~n vacuo
over potassium hydroxide, glving ethyl (Z)-2-(hydroxy-
S imino)-3-oxobutyrate (309 g).
A stirred and ice-cooled solution of ethyl (Z)-2-
(hydroxyimino)-3-oxobutyrate (150 g)-in dichloromethane
(400 ml) was treated dropwise with sulphuryl chloride
(140 g). Th~ resulting solution was kept at room temp-
erature for 3 days, then evaporated. The residue wasdissolved in diethyl ether, washed with water until the
washings were almost neutral, dried, and evaporated. The
residual oil (177 g) was dissolved in ethanol (500 ml)
and dimethylaniline (77 ml) and thiourea (42 g) was added
with stirring. After two hours, the mixture was
filtered and the residue washed with ethanol and dried to
give the title compound (73 g); m.p. 188 (decomp.).
Preparation 2
Ethyl (Z)-2-hydroxyimino-2-(2-trit~L~LL~c ~ gl g yl)-
acetate, hydrochloride
Trityl chloride (16 75 g) was added portionwiseover 2 hours to a stirred and cooled (-30) solution of
the product of Preparation 1 (12.91 g) and triethylamine
(8.4 ml) in dimethylformamide (28 ml). The mixture was
allowed to warm to 15 over one hour, stirred for a
further 2 hours and then partitioned between water (500
ml) and ethyl acetate (500 ml). The organic phase was
separated, washed wlth water ~2 x 500 ml) and then
shaken with lN HCl (500 ml~. The precipitate was
collected, washed successively with water (100 ml), ethyl
acetate (200 ml) and ether (200 ml) and dried in vacuo to
113~8
- 29 -
provide the title ~ as a white solid (16. 4 g);
m.p. 184 to 186 (decomp.).
Preparation 3
Ethyl (2?-2-(2-t-butoxycarbonyl~rop-2-oxyimino)-2-(2-
5 tritylaminothiazol-4-yl)acetate
Potassium carbonate (34.6 g) and t-butyl 2-bromo-
2-methylpropionate (24.5 g) were added to a stirred solu-
tion under nitrogen of the product of Preparation 2
(49. 4 g) in dimethylsulphoxide (200 ml) and the mixture
10 was stirred at room temperature for 6 hours. The mixture
was poured into water (2 1), stirred ~or 10 mins., and
filtered. The solid was washed with water and dissolved
in ethyl acetate (600 ml). The solution was washed
successively with water, 2N hydrochloric acid, water, and
15 saturated brine, dried, and evaporated. The residue was
recrystallised from petrol to give the title compound (34
g), m.p. 123. 5 to 125.
Preparation 4
(Z)-2-(2-t-ButoxycarbonYlprop-2-oxyimino~-2-(2-trit~
- 20 aminothiazol-~yl)acetic acid
The product of Preparation 3 (2 g) was dissolved in
methanol (20 ml) and 2N sodium hydroxide (3.3 ml) was
added. The mixture was refluxed for 1.5 hours and then
concentrated. The residue was taken up in a mixture of
25 water (50 ml), 2N hydrochloric acid (7 ml), and ethyl
acetate (50 ml). The organic phase was separated, and
the aqueous phase extracted with ethyl acetate. The
organic solutions were combined, washed successively with
water and saturated brine, dried and evaporated. The
~3~8
- 30
residue was recrystallised from a mixture of carbon
tetrachloride and petrol to give the title compound (1 g),
m.p. 152 to 156 (decomp.).
Preparation 5
Ethyl (Z)-2-(2-tritylaminothiazol-4-yl)-2-(1-t-butoxy-
carbonylc~clobut-l-oxyimino) acetat_
The product of Preparation 2 (55.8 g) was stirred
under nitrogen in dimethylsulphoxide (400 ml) with
potassium carbonate (finel~ ground, 31.2 g) at room
temperature. After 30 minutes, t-butyl l-bromocyclo-
butanecarboxylate (29.2 g) was added. After 8 hours
further potassium carbonate ~31.2 g) was added~ More
potassium carbonate (6 x 16 g portions) was added during
the nex-t three days and further t-butyl l-bromocyclo-
butanecarboxylate (3.45 g) was added after 3 days. After4 days in all, the mixture was poured into ice-water (caO
3 litres) and the solid was collected by filtration and
washed well with water and petrol. The solid was
dissolved in ethyl acetate and the solution washed with
brine (twice), dried with magnesium sulphate and evapor-
ated to a foam. This foam was dissolved in ethyl acetate-
petrol (1:2) and filtered through silica gel (500 g).
Evaporation gave the title compound (60 g) as a yellow
foam, ~ (CHBr3) 3400 (NH) and 1730 cm (ester).
~
(Z)-2~ t-Butoxycarbonylc clobut-l-o imino)-2 (2-trityl-
~ _ _ y_ xy
aminothiazol-4-yl) acetic acid
A mixture of the product of Preparation 5 ~3.2 g3
and potassium carbonate (1.65 g) was refluxed in methanol
,
,
"
3L3~
- 31 -
(180 ml) and water (20 ml) for 9 hours and the mixture
was cooled to room temperature. The mixture was concen-
trated and the residue partitioned between ethyl acetate
and water, to which was added 2N HCl (1202 ml). The
organic phase was separated and the aqueous phase
extracted with ethyl acetate~ The combined organic
extracts were washed with saturated brine, dried and
evaporated to give the title compound (2.3 g); Amax
(ethanol) 265 nm (El/m243).
Example 1
a) Diphenylmethyl (lS,6R,7R~-3-Bromomethyl-7-[(Z)-2-(2-t-
butoxycarbonyl~rop-2-oxyimino)-2-(2-tritylaminothiazol-4-
yl)acetamido]ce~h-3-em-4-carboxylate, l-Oxide
A solution of the product of Preparation 4 (0.526 g)
in dry tetrahydrofuran (6 ml) was treated successively with
l-hydroxybenztriazole monohydrate (0,141 g) and
N,N'-dicyclohexylcarbodiimide (0.198 g) in tetrahydrofuran
(4 ml). The developing suspension was stirred for 30
minutes at 23O and then filtered. A solution of diphenyl-
methyl (lS,6R,7R) 7-amino-3-bromomethylceph-3-em-4-
carboxylate~ 1 oxide (0.427 g) in dichloromethane (260 ml)
was treated at 23O with the above filtrate. The solution
was stirred for 18 hours at 20O to 25, Qvaporated to
dryness, then the residue was dissolved in dichloromethane
and washed successively with saturated aqueous sodium bicar-
bonate~ water and brine, then dried and evaporated in vacuo
to a foam (1.01 g).
This foam was purified by chromatography on
- 32 -
preparative silica plates using toluene:ethyl acetate:acetic
acid = 190:50:2.5 as eluant. The purified product was
isolated as a foam which was dissolved in ethyl acetate
(5 ml) and precipitated from petrol (200 ml) to give the
title compound (0.69 g) as a colourless powder; ~max (EtOH)
268 nm (ElCml82) with an inflection at 242 nm El 230),
i~ vmax(Nujol~ 3375 (NH), 1805 (~-lactam), 1730 (C02R) and
1688 and 1515 cm 1 (CONH).
b) Dipheny methyl (lS?6Rj7R~-7-C(Z)-2-(2-t-butoxycarbonYl-
~ 4 y1~ ~cet o ~3-
trimethylammoniomethylceph-3-em-4-carboxylate~ l-Oxide,
Bromide Salt
The product of stage a) (0.154 g), alumina-dried
tetrahydrofuran (0.3 ml) and anhydrous trimethylamine in
dry tetrahydrofuran (0.155 g of trimethylamine in 1 ml of
solution) (0~065 ml) were stirred at 24 for 1 hour. The
reaction mixture was added dropwise to well-stirred ether
(220 ml) and the resulting suspension was stirred
vigorously for 10 minutes. The solid was filtered off,
washed with ether and dried in vacuo to give the title
compound (0.131 g) m.p. 158 to 178 (decomp.); ~a]D +
11 (c 0.53, CHC13).
I rade /~ k
, ~ ,
.
3~
- 33 -
c) Diphenylmethyl (6R,7R)-7- r ( z ) - 2-(2-t-Butoxycarbonyl-
prop-2-oxyimino~-2-~2-tritylaminothiazol-4-vl)acetamido]
3-trimethylammoniomethylceph-3--em-4-carboxylate~ Iodide
Salt
The product of stage b) (1.87 g) and acetone (4.7
ml) were stirred at -10 as a solution. Dry, powdered
potassium iodide (lo 14 g) was added and the mixture was
stirred at -10 for 2 minutes. Dry, powdered potassium
iodide (1.14 g) followed by acetyl chloride (0.25 ml)
were added and the vigorously stirred mixture was allowed
to warm to 0 over 20 minutes. The mixture was stirred
at 0 to ~2 for 1 hour. The mixture was added dropwise
to a stirred solution of sodium metabisulphite (0.850 g)
in water (47 ml). The resulting solid was filtered off,
washed with water and dried in vacuo over phosphorus pent-
oxide to gi~e a solid (1.939 g). The above procedure was
repeated using the solid (1.87 g), acetone (4.7 ml), dry
powdered potassium iodide (1.14 g), acetyl chloride (0.25
mlj and a reaction time at 0 to +2 of 25 minutes. This
gave the title compound (1.951 g) as a solid, m.p. 142 to
176; [a]2-716 (c 0.38, CHC13).
d) Diphenvlmethvl (6R.7R~-7-r(Z~2-(2-t-Butoxycarbony~
prop-2-oxyimino?-2-(2~tritylaminothiazol-4-yl)-acetamido~-
acetate Salt
The product of stage c) (1.826 g) was dissolved in
acetone:ethanol = 9:1 and chromatographed on "Deacidite"l
FF SRA 62 ion exchange resin (strong anion exchange resin)
trifluoroacetate form. The column was eluted with the
- 34 ~
above solvent mixture. A forerun of 20 ml was discarded
and the next 250 ml were evaporated in vacuo immediately
to give the title ~E~ (1.595 g) as a red-brown foam.
e) (6R,7R)-7-~(Z)-2-(2-Aminothiazol-4-yl)~2-(2-carboxy-
prop-2-oxvimlno)acetamido~-3-trimethylammoniomethylceph~
3-em-4-carboxyl~te
The product of stage d) (1.37 g), anisole (1.37 ml)
and trlfluoroacetlc acid (5.5 ml) were swirled together at
25 for 1~ minutes, when a solution was formed, and then
for a further 1 minute. The volatile material was evap-
orated off and the residue was azeotroped with toluene
(twice). The gum was dissolved in acetone (10 ml) and
preclpitated into petrol (500 ml3. The brown solid was
flltered off~ washed wlth petroleum ether and dissolved in
acetone. The solution was evaporated to a foam (1.117 g).
The foam (1.117 g), anisole (0.25 ml) and tri- -
fluoroacetic acid (5 ml) were swirled together at 28 for
5 minutes. The volatile material was removed and the
residue was azeotroped with toluene (twice). The result-
ing brown oil was precipitated with acetone (10 ml) and
40 to 60 petroleum ether (500 ml) to give a solid (1.066
g)-
The solid (0.2 g) was dissolved in trifluoroa~eticacid:water = 1:1 (2 ml) and the solution was stirred at
28 for 30 minutes. The mixture was evaporated to dry-
ness and the resulting gum was dissolved in water (10 ml).
The cloudy solution was filtered, the-residue was washed
with water (10 ml, 5 ml) and the filtrate was free~e-
dried to give a foam, (0.17 g). The foam was triturated
1 ~ 3
- 35 -
with ether, the solid obtained was filtered rapidly and
dried in vacuo to give the title compou~ (0.148g) as a
solid associated with 1.8 moles of trifluoroacetic acid;
[~]~ ~ 120 (c 0.3; EtOH:H20 = 1~ inf (pH6 buffer~
230 nm (~ 17,000), ~ inf 260 nm (~ 10,200).
Example ~
a) Diphenylmethyl (lS,6R,7R~-3-Bromomethyl-7- r (z) - 2-
(l-t-butoxycarbonylcyclobut-l-oxyimino)-2-(2-tritylc~min
tlliazol-4-yi~acetaLllido~-cep;l-~-erll-4-carboxYiate~ 1 Oxiae
A stirred solution of the product of Preparation 6
(1.167 g) in tetrahydrofuran (15 ml) was treated
successively with l-hydroxybenztriazole hydrate (0.337 g)
and N,N'-dicyclohexylcarbodiimide (0.495 g) for 30
minutes at 220.
Filtration afforded a solution of the activated
ester which was added to a solution of diphenylmethyl
(lS~6R~7R)-7-amino-3-bromomethylceph-3-em-4-carboxylate
l-oxide (0.95 g) in dichloromethane (550 ml). The solution
was stirred for 16 hours then evaporated to dryness. A
solution of the residue in dichloromethane was washed
successively with aqueous sodium bicarbonate, and brine,
and then dried and evaporated to a foam (2.2 g) which was
purified by preparative thin-layer chromatography ~using
toluene;ethyl acetate:acetic acid = 40:10:1 for
development) to give the title compound (1.4 g) with
~maX(EtOH) 266 nm (ElCml92) and an inflection at 242.5 nm
- 36 -
(ElCm224), vmax(Nujo~ 3360 (NH)~ 1805 (~-lactam),
1730 (C02R) and 1689 and 1520 cm 1 (CONH).
b) Diphenylmethyl (lS,6R,7R)-7-~(Z)-2-(l-t-ButoxYcarbonyl-
cyclobut-l-oxy mino)-2-(_-tritylaminothiazol-4-Yl~-
acetamido]-3-trimethylammoniomethylceph-3-em-4-carboxyl
ate l-Oxide Bromide Salt
The product of stage a) (1.2 g), alumina-dried
tetrahydrofuran (205 ml) and anhydrous trimethylamine in
dry tetrahydrofuran [O. 49 ml of a solution of trimethyl-
amine (0.155 g) in tetrahydrofuran (1 ml)~ were stirred at
24 for 30 minutes. The reaction mixture was added drop-
wise to stirred ether (900 ml~ and the resulting sus-
pension was stirred vigorously for 10 minutes. The solid
was filtered off, washed with ether and dried in vacuo to
give the title compound (1.16 g), m.p. 156 to 170
(decomp); [a~D ~ 6 (c 0. 48, CHCl3).
c) Diphenylmethyl ~6R~7R~-7-r(z2--2-(l-t-Butoxvcarbon
cyclobut-l-oxyimino2~(2-tritylaminothiazol-4-yl)-
acetamido~-3-trimethylammoniomethylcep~-em-4-carboxylate,
Iodide Salt
The product of stage b) (1.05 g) and acetone (2.6
ml3 were stirred as a solution at -10. Dry, powdered
potassium iodide (0.625 g) was added and the mixture was
stirred at -10 for 2 minutes. Further dry, powdered
potassium iodide (0.625 g) das added followed by acetyl
chloride (0.14 ml). The stirred mixture was allowed to
warm to 0 and it was stirred at 0 to +2 for 3~ hour~
~ ~ 3
- 37 -
The mixture was added dropwise to a stirred solution of
sodium metabisulphite (0.465 g) in water (26 ml). The
resulting solid was filtered off, washed with water and
dried in vacuo over phosphorus pentoxide to give a solid
(1.072 g). The above procedure was repeated using the
solid (1.072 g), acetone (2.6 ml), dry, powdered
potassium iodide (0.625 g), and acetyl chloride (0.14 ml)
to give the title compound (1.131 g) as a solid, m.p. 133
to 170 (decomp) [a~D-33 (c 0.6, CHC13).
d) (6R?7R)-7-[~Z)-2-(2-Amin thiazol;4-yl)-2-(1-carbox~-
cyc_ but-l-oxYimino)ac_ ~mido~-3-trimeth~Lammoniomethyl--
ceph-3-em-4-carboxY~te
The product of stage c) (0.2 g) was wetted with
anisole (0.2 ml) and trifluoroacetic acid (0.8 ml) was
added. An immediate precipitate was formed and the
suspension was swirled for 2 minutes at ca 23 when the
precipitate became gummyO The mixture was evaporated to
dryness and the residue was triturated with ether to give
a solid which was wetted with anisole (0.035 ml) and tri-
fluoroacetic acid (4 ml) was added. A very fine precipi-
tate formed and the suspension was swirled at 23 for 15
minutes. The mixture was evaporated to a gum which was
triturated with ether to gi~e the title compound (0.091 g~
as a solid, associated with 1 mole of trifluoroacetic
acid and 0.4 mole of hydrogen iodîde, Ea~D ~ 45
(c 0.22, ethanol:water = 1~ inf (pH 6 buffer) 257.5 nm
(El/ 240), ~ inf 296 nm (ElCm 115).
- 38 ~ 8
Example 3
a) Diphenylmethyl (lS~6R,7R~-7-~(Z)-2-(1-t-Butoxycarbonyl-
cyclobut-l-oxyimino)-2-(2-tritylaminot ~
acetamido]-3-dimethylaminomethylceph-3-em-4-carboxylate~ 1-
Oxide
The product o Example 2(a) (0.52 g) in dry
tetrahydrofuran (2 ml) was treated with a solution of
dimethylamine in ethanol (33% w/w; 0.20 ml). ~fter 15
minutes at 21, the mixture was partitioned between ethyl
acetate (25 ml) and water (25 ml). The aqueous layer was
extracted with more ethyl acetate (25 ml) and the total
organic solution was washed with water (2x50 ml) and dried
(Na2S04) and evaporated to a foam (0.498 g). The crude
product was purified by preparative thin-layer chroma-
tography on silica-gel plates (2mm thick) eluted with ethyl
acetate. The main band, Rf 0.4 yielded a foam (0.331 g)
which was dissolved in ethyl acetate (2 ml) and added
slowly to stirred petrol (50 ml)O The precipitate was
filtered off and washed with petrol and dried in vacuo to
give the title compound (0.224 g) as a solid, ~]D-21
(c 0-87%~ G~Cl~ inf(EtOH) 245 nm (El/D 225), 260 (El 210
and 305 nm (ElCm57).
b)
~
The product from stage (a) (01201 g) was dissolved
in iodomethane (1 ml) and the solution was left to stand
~3~
at 21 for 1~ hours. Diethyl ether (20 ml) was added, and the precipitate was
tri~urated and then filtered off and washed with ether and dried in vacuo to
give the title ~e~_ d (0.199 g) as a solid, [~]D~10 (c 0.87~J CHC13),
~inf(EtOH) 260 nm (ElCm160), 265 nm (E1%Cml54) and 305 nm (ElC~n64) with a ~ max
at 394 nm (ElCm43).
The title compound may be converted into (6R,7R)-7-[(Z)-2-(2-
aminothiazol-4-yl)-2~ carboxycyclobut-1-oxyimino)acetamido]-3-trimethyl-
ammoniomethylceph-3-em-4-carboxylate as described in Example 2.
Example 4
a) Diphenylmethyl (lS,6R,7R)-7-~ormamido-3-trimethylammoniomethylceph-3-em-4-
carboxylate, l-oxide, Bromide Salt
A solution of diphenylmethyl (lS,6R,7X)-3-bromomethyl-7-formamido-
ceph-3-em-4-carboxylate, l-oxide (1.01 g) in dry N,N-dimethylformamide (3 ml)
was treated with a solution (0.8 ml) of anhydrous trimethylamine in tetrahydro-
furan (0.155 g of trimethylamine per ml of solution) and the solution was stirred
at 21 for 15 minutes. Ether (10 ml) was added and the supernatant solution was
discarded. Trituration of the oily residue with ether (ca. 15 ml) gave a
precipitate which was filtered off, washed with ether and dried rapidly in vacuo
to give the title compound (1.002 g) as a solid m.p. 140 to 150 (with
decomp), Vmax(Nujol) ca. 3400 (NH), 1798 ~B-lactam), 1680 (C=O of HCONH),
1732 (CO2R), and 1035 cm 1 (sulphoxide).
b) Diphenylmethyl (lS,6R,7R)-7-Amino-3-trimethylammoniomethylceph-3-em-4-
carboxylate, l-Oxide, Hydrochloride and Bromide Salts
A mixture of the product of stage (a) (0.562 g) in methanol (5 ml)
was stirred at 0 and treated~ dropwise, with phosphoryl chloride (0.28 ml)
over 10 minutes. The mixture was stirred at 0 for 2 hours to precipitate a
;~ -39-
- 40 -
buff solid. Ether (15 ml) was added to the stirred mixture
then the precipitate was filtered off and washed
successively with ether and ethyl acetate and dried in
vacuo to give the title compound (0.479 g) as a solid,
~` 5 ~maX(EtOH) 280 nm (ElCmll7), vmax(Nujoi~ 3700 to 2200 (~ 3),
1807 (~-lactam) and 1734 cm 1 ~C02R).
c) Diphenylmethyl (lS,6R~Z~-7-C(7)-2-(2-t-Butoxycarbonyl-
prop-2-ox~imino)-2-(2-trit~laminothiazol-4-y~acetamidol
3-trimethylammoniomethy~ceph-3-em-4-carboxylate L 1 - Oxide,
Bromide Salt
Phosphorus pentachloride (0.11 g), in dry
dichloromethane (10 ml) at 0 was treated with the product
of Preparation 4 and the solution was stirred at 0 for
35 minutes Triethylamine (0.16 ml) was added
and stirring was continued at 0 for 5 minutes. The
solution was then added dropwise, over 5 minutes to a
vigorously stirred suspension of the product of stage (b)
(0.286 g) in dichloromethane (15 ml) at 0O The
suspension was stirred at 0 for 15 minutes, 20 for 2
hours and was then allowed to stand at 40 overnight.
The mixture was partitioned between ethyl acetate
(100 ml) and water (100 ml) and the emulsion was
clarified by filtration. The organic phase was washed
with water (100 ml~ then dried over sodium sulphate and
evaporated to a foam. A solution of this foam in ethyl
acetate (4 ml) was added dropwise to stirred petrol
(120 ml). The precipitate was filtered off and washed
with petrol and dried in vacuo to give the crude product
(0.363 g) as a solid. Some solid remained on the sinter;
~ ~ 3
- 41 -
this was dissolved in ethyl acetate and the solution
evaporated to a gum (0.019 g). The above combined
products (0033 g) were stirred with ethyl acetate (20 ml)
for 15 minutes with trituration of the precipitate. The
stirred mixture was slowly diluted with ether (20 ml) and,
after a further 10 minutes 3 the solid was filtered off and
washed with ether and dried in vacuo to give, the title
(O.211 g~ as a solid, ~inf(EtOH) 240 nm (ElCm214),
260 nm (E~ml59), 266 nm (ElCml50), 272.5 nm (ElCml40) and
305 nm (El 68)with ~max at 385 nm (Elcm32)' ~max(CHBr3)
3670 (water), 3600 to 2500 (NH), 1804 (~-lactam), 1730
(C02R)j 1680 and 1513 cm (CONH).
The title compound may be converted into (6R,7R)-
7-C(Z)-2-'(2-Aminothiazol-4-yl)-2-(2-carboxyprop-2-oxyimino)
acetamido]-3-trimethylammoniomethvIceph-3-em-~4-car~ox~late^
as described in Example 1.
- 42 -
The antibiotic compounds of the invention may be
formulated for administration in any convenient way, by
analogy with other antibiotics and the invention therefore
includes within its scope pharmaceutical compositions
comprising an antibiotic compound in accordance with the
invention adapted to use in human or veterinary medicine.
Such compositions may be presented for use in conventional
manner with the aid of any necessary pharmaceutical
carriers or excipients.
The antibiotic compounds according to the invention
may be formulated for injection and may be presented in
unit dose form in ampoules, or in multi-dose containers,
if necessary with an added preservative. The compositions
may also take such forms as suspensions, solutions, or
emulsions in oily or aqueous vehicles, and may contain
formulatory agents such as suspending, stabilising and/or
dispersing agents. Alternatively the active ingredient
may be in powder form for reconstitution with a suitable
- vehicle, e.g. sterile, pyrogen-free water, before use.
If desired, such powder formulations may contain
an appropriate non-toxic base in order to improve the
water-solubility of the active ingredient and/or to
ensure that when the powder is reconstituted with water,
the pH of the resulting aqueous formulation is physio-
logically acceptable. Alternatively, the base may be
present in the water with which the powder is reconstit-
uted. The base may be, for example, an inorganic base
- 43 -
such as sodium carbonate, sodium bicarbonate or sodium
acetate, or an organic base such as lysine or lysine
acetate.
The antibiotic compounds may also be formulated as
suppositories, e.g. containing conventional suppository
bases such as cocoa butter or other glycerides.
For medication of the eyes or ears, the prepara-
tions may be formulated as individual capsules, in liquid
or semi~solid form, or may be used as drops.
Compositions for veterinary medicine may, for
example, be formulated as intramammary preparations in
either long acting or quick-release bases
The compositions may contain from 0.1% upwards,
e.g. 0.1-99%, of the active material, depending on the
method of administration. When the compositions comprise
dosage units, each unit should preferably con~ain 50-1500
mg of the active ingredient. The dosage as employed for
adult human treatment will preferably range from 500 to
6000 mg per day, depending on the route and frequency of
administration. For example, in adult human treatment
1000 to 3000 mg per day administered intravenously or
intramuscularly ~hould normally suffice. In treating
Pseudomonas infections higher daily doses may be required.
The antibiotic compounds according to the invention
may be administered in combination with other therapeutic
agents such as antibiotics, for example penicillins or
other cephalosporins.
~ ~ 3
- 44 -
The following formulation illustrates how a
compound according to the invention may be made up into
a pharmaceutical composition.
Formulatin ~
Formula Per Vial
(6R,7R)-7- C(2)-2-(2-Aminothiazol-4-yl)-2-(l-earboxycyelo-
but-l-oxyimino)-aeetamido~-3-trimethylammoniomethyl-eeph-
3-em-4-carboxylate 500 mg
Sodium carbonate, anhydrous ~9 mg
Method
Blend the sterile cephalosporin antibiotic with
sterile sodium carbonate under aseptic conditions Fill
aseptically into glass vials under a blanket of sterile
nitrogen.` Close the vials using rubber discs, or plugs,
held in position by aluminium overseals, thereby
preventing gaseous exchange or ingress of microorganisms.
Reconstitute the product by dissolving in Water for
Injections or other suitable sterile vehicle shortly before
administration.
,
-
. ~
r
