Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
L6
~ hl'5 application is a divisional of our copending
Canadian Patent Application Serial No. 207,441 filed August 20,
1974.
This invention is concerned with improvements in
or relating to antibiotics of the cephalosporin series.
The cephalosporin compounds in this specification
are named with reference to "cepham" after J.Amer. Chem.
Soc., 1962, 84, 3400, the term "cephem" referring to the
basic cepham structure with one double bond.
Man~ cephalosporin compounds possessing a
degree of antibacterial activity are known in the art,
these compounds possessing ~ unsaturation and ordinarily
being substituted at the 3-position by a methyl or
substituted methyl group and at the 7~-position by an
acylamido group. It is now well recognised that the
antibiotic properties of a particular ceph-3-em~4-carboxy-
lic acid are predominantly controlled by the nature of both
the 7~-acylamido group thereof and the 3-position
substituent which the compound carries; considerable
research has been undertaken to find combinations of such
groups which will yield antibiotics with particular pro-
perties.
Cephalosporin antibiotics are widely used in $he
treatment of diseases caused by pathogenic bacteria in
human beings and animals, for example in the treatment
of diseases caused by bacteria which are resistant to
0~
- 2 ~
~ 6
other antibiotics such as penicillin compounds and in the
treatment of penicillin-sensitive patients. In many
applications it is desirable to employ a cephalosporin
antibiotic which exhibits activity against both gram
positive and gram negative microorganisms, and a
significant amount of research has been directed to the
development of improved broad spectrum cephalosporin
antibiotics.
The practical utility of a significant
number of known commercial and experimental cephalosporin
antibiotics is limited by their relatively high
susceptibility to the ~-lactamases which are produced
by many bacteria. A desirable property of a broad
spectrum cephalosporin antibiotic is therefore that it
should exhibit substantial resistance to ~lactamases,
including those produced by gram negative microorganisms.
A further difficulty with many cephalosporin
antibiotics intended for therapeutic applications is that
they are subject to degradation in vivo. Thus a
significant number of known cephalosporin antibiotics
have been found to suffer the disadvantage that following
.administration they are deactivated, often rapidly,
-- 3
~048(~6
by enzymes (e,g, esterases) present in the body.
As a result of prolonged ~tudies of numerous
cephalosporin compou~ds we have now found a class of
cephalosporln antibiotics having a particular combination
of 7~-acylamido group and 3-position substituent which
endows the compounds with good broad spectrum activity
coupled with the above-described desiderata of high
~-lactamase stability and good stability in vivo.
These compounds are characterised in that the 7~-acylamido
group is a 2-aryl-2-(etherified oxyimino)acetamido group
which is substantially in the s~n configuration (as
hereinafter defined) and that the 3-substituent is a
carbamoyloxymethyl group.
The present invention, therefore provides anti-
biotic compounds of the general formula
H H
,
R c.CONH l I ~ S ~ (I)
OR N~ ~ - CH20.CO.NH2
COOH
(where R represe~ts a furyl, thienyl or phenyl group
and R2 represents a Cl-C4 alkyl group, a C3-C7 cycloaIkyl
_ 4 _
~4~16
group or a phenyl group except that R2 may not represent
a methyl group when Rl represents a furyl group) and non-
toxic salts, biologically acceptable esters,l-oxides and
solvates thereof,the compounds being ~y~ isomers or existing
as mixtures of syn and anti isomers containing at least
90% of the syn isomer. Most preferably the compounds
are the syn isomers essentially free from the corresponding
anti isomers,
The compounds of the invention are def-lned as
having the sYn (cis) isomeric form as regards the con-
figuration of the group oR2 with respect to thecarboxamido
group In this specification the ~y~ configuration is
structurally denoted thus:-
R .C.CONH-
oR2
The syn configuration is assigned on the basis of the
work of Ahmad and Spenser as reported in Can, J. Chem.
1961, 39, 1340.
The term "non-toxic"as applied to salts, esters, 1-
oxides and solvates (especially hydrates) of the compounds
of the invention means such derivatives which are physiol-
ogically acceptable in the dosage at which they are
. . 1048~6
admlnlstered.
Salts which may be formed from the compounds of
general formula I include inorganic base salts such
as alkali metal (e.g. sodium and potassium),alkaline
earth metal (e.g. calcium) and organic base (e.g.
procaine, phenylethylbenzylamine, dibenzylethylene-
diamine, ethanolamine, diethanolamine, triethanolamine
and N-methylglucosamine) salts. The salts may also
comprise resinates, formed with, for example a polystyrene
resin or cross-linked polystyrene divinylbenzene copolymer
resin containing amino or quaternary amino groups.
Where R in general formula I is a furyl group
it may be fur-2-yl or fur-3-yl and when it is a thienyl
group it may be thien-2-yl or thien-3-yl.
As indicated above, the group R2 in formula I
represents an alkyl group containing 1-4 carbon atoms, e.g,
a methyl, ethyl or t-butyl group; a cycloalkyl group
containing 3-7 carbon atoms, e.g. a cyclopentyl group;
or a phenyl group.
. .
~ 6
The compounds of formula (I), as indicated above,
possess a particularly valuable combination of properties,
exhibiting high antibacterial activity against a broad
range of gram-positive and gram-negative organisms
The breadth of the activity spectrum is enhanced by
the particularly high stability of the compounds to .~-
lactamases produced by various gram-negative organisms
The compounds show the advantageous property of good
stability in ViVQ, parti~ularly to esterases
The properties possessed by the compounds of
formula (I) render them useful in the treatment of a
variety of diseases caused by pathogenic bacteria in
human beings and animals.
~0480~6
Where insoluble salts of the compound (I) are
desired in a particular application, for example for use
in depot preparations, such salts may be formed in
conventional manner, for example wi-th appropriate
organic amines.
The invention further provides a process for the
preparation of an antibiotic compound of formula I
(as hereinbefore defined~ or a non-toxic salt, biologic-
ally acceptable ester, l-oxide or solvate thereof which
comprises either (A~ condensing a compound of general
formula
E~
H2N , '~ ~
O ~ CH20.CO NHR12 ~II)
COORl 1
(wherein B is = S or = S~ O; R is hydrogen or a
carboxyl blockinggroup, e.g. the residue of an ester-
forming aliphatic or araliphatic alcohol or an ester-
forming phenol, silanol or stannanol, or a symmetrical
or mixed anhydride group derived from an appropriate
acid; R 2 is hydrogen or an N~protecting group, e.g
-- 8 --
1C1148~1~
an acyl group, especially a lower alkanoyl group such as
acetyl, a hal~-substituted lower alkanoyl group such
as mono~, di- or tri-chloroacetyl, or a chlorosulphonyl
- group) or an acid addition salt thereof(e,g, an
acid addition salt formed with, for example, a mineral
: acid such as hydrochloric, hydrobromic,sulphuric, nitric
or phosphoric acid or an organic acid such as methane
sulpho~ic or toluene p-sulphonic acid) or an N-silyl
derivative thereof, with:an acylating agent corresponding
10 to the acid
Rl,C.COOH
ll (III)
N oR2
(wherein R and R2 have the above-defined meanings),
or (B) reacting a compound of the formula
H H
R ,C.CO,NH ~ I - r B ~
N ~ oR2 O ~ N ~ CH2H (IV)
COOR
g
~V~80~6
(wherein Rl, R2, B and Rll have the above defined
meanings) with a carbamoylating agent serving to form
a carbamoyloxy-methyl group or an N-protected carbamoyloxy-
methyl group at the 3-position; whereafter, if
necessary and/or desired in each instance, any of the
following reactions (C), in any appropriate sequence
are carried out:-
(i) removal of any carboxyl blocking or N-protecting
groups, and (ii)ireduction of a cephalosporin sulphoxide
product to yield the corresponding sulphide; and finally
(D) recovering the desired compound of formula I if
desired after conversion of the compound to a non-toxic
salt,biologically acceptable ester, l-oxide or solvate
.
thereof,
Non-toxic derivatives of the compounds of formula I
may be formed in any convenient way, for example accord-
ing to methods well known in the art, Thus, for example,
base salts may be formed by reaction of the cephalosporin
acid with sodium or potassium 2-ethylhexanoate. Bio-
logically acceptable esterderivatives may be formed
using conventional esterifying agents. l-Oxides may
be formed by treatment of the corresponding cephalosporin
sulphide with an appropriate oxidising agent, for
example with a peracid such as metaperiodic acid,perac~tic
- 10 -
1~48~L6
acid, monoperphthalic acid or m-chloroperbenzoic
acid, or with t-butyl hypochlorite conveniently in the
presence of a weak base such as pyridine,
Compounds of formula I may conveniently be prepared
by condensing a compound of formula (II) with an acylating
"
~48g;)~;6
agent comprising an acid halide, particularly an acid
chloride or bromide, corresponding to the acid (III).
Such acylation may be effected at temperatures of from
-50 to +50C, preferably -20 to ~30C. The acylation
may be effected in aqueous or non aqueous media.
Acylation with an acid halide may be effected in
the pres~nce of an acid binding agent (e.g. a tertiary
amine such as triethylamine or dimethylaniline, an
inorganic base such as calcium carbonate or sodium bi-
carbonate, or an oxirane, preferably a lower-1,2-
alkylene oxide such as ethylene oxide or propylene oxide)
which serves to bind hydrogen halide liberated in the
acylation reaction.
The free acid form of a compound of formula (III)
may itself be used as the acylating agent. Such
acylations are desirably conducted in the presence
of, for example, a carbodiimide such as N,N'-diethyl-,
dipropyl- or diisopropylcarbodiimide, N,N'~dicyclohexyl-
carbodiimide, or N-ethyl-N'-~-dimethylamLnopropylcar-
bodiimide; a carbonyl compound such as carbonyldiimidazole;
- 12 -
8~6
or an isoxazolinium salt such as N-ethyl-5-ph~ylisoxa-
zolinium-3'-sulphonate or N-t-butyl-5-methyliso~azolinium
perchlorate. The condensation reaction is desirably
effected in an anhydrous reaction medium, e.g. methylene
chloride, dimethylformamide or acetonitrile.
Acylation may also be effected with other amide-
forming derivatives of the free acid (III) such as,
for example, a symmetrical anhydride or a mixed anhydride,
e,g. with pivalic acid or formedwith a haloformate
such as a lower alkyl haloformate. The ~ixed or
symmetrical anhydrides may be generated in situ.
Thus, for example, a mixed anhydride may be generated
using N ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline.
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 p-toluenesulphonic acidj.
Where a starting material of formula (IV) is
employed, suitable carbamoylating agents include
isocyanates of general formula
R13 NC0 (V)
- 13 -
~ 8~16
where R13 is a labile substituent group; such carbamoylating
agents serve to form at the 3-position an N-protected
carbamoyloxymethyl group of formula
--CH20, CO . NHR13
(where R13 has the above~defined m~aning) which may be
converted to the desirèd unsubstituted 3-carbamoyloxymethyl
group by subsequent cleavage of the group R13, for example
by hydrolysis,Labile groups R13 which are readily cleavable
upon such subsequent treatment include chlorosulphonyl and
bromosulphonyl; aralkyl.groups such as benæyl, ~-methoxybenzyl
and diphenylmethyl; t-butyl; halogenated lower alkanoyl
groups such as dichloroacetyl and trichloroacetyl; and halo-
genated lower alkoxycarbonyl groups such as 2,2,2-
trichloroethoxycarbonyl, R 3 groups of this type, with the
exception of aralkyl groups such as diphenylmethyl, may -
generally be cleaved by acid or base catalysed hydrolysis
(e.g, by base catalysed hydrolysis using sodlum bicarbonate)
Halogenated groups suc~.as chlorosulphonyl, trichloroacetyl
and 2,2,2~trichloroethoxycarbonyl may also be cleaved re-
ductively, while groups such as chloroacetyl may also becleaved by treatment with ~hioamides such as thioure~. Aralkyl
- 14
~(~48~6
groups such as diphenylmethyl are conveniently cleaved by
treatment with acid, e.g. a strong organic acid such as
trifluoroacetic acidO
The carbamoylating agent of formula (V) is desirably
used in excess(for example at least 1.1 moles relative
to the compound of formula (-IV) The carbamoylation may be
assisted by the presence of base, e.g. a tertiary organic
base such as a tri-(lower alkyl)amine (e.g. triethylamine)
or by employing the acid(IV)in the form of an alkali
metal (e.g. sodium) salt, although such assistance may not
be necessary in the case of more active isocyanates, e.g.
compounds ~V) when R is a strongly electron-withdrawing
group such as chlorosulphonyl or trichloroacetyl.
Carbamoylations involving reaction of a free acid (1~
with excess isocyanate (V~ wherein R13 is a group such
as chlorosuIphonyl or trichloroacetyl are thus of particular
practical advantage by virtue of the simplicity of the
reaction conditions, since there is no need for temporary
blocking and subsequent deblocking of the 4-position
carboxy group of the cephalosporin and since the electron
withdrawing R group in the resulting N-protected 3
- 15
1~4~ 6
-carbamoyloxymethyl cephalosporin product is readily
removed by, for example, hydrolysis with aqueous sodium
bicarbonate .
It should be noted that it may be convenient to
retain or even to introduce an N-substituting group R
during trans~ormations of;intermediate 3-carbamoyloxymethyl
compounds in order to minimise unwanted side reactions
involving the carbamoyloxymethyl ~roup. .
Another useful carbamoylating agent is cyanic acid,
which is conveniently generated in situ from, for example,
an alkali metal cyanate such as sodium cyanate, the
reaction being facilitated by the presence of an acid,
e.g. a strong organic acid such as trifluoroacetic acid.
Cyanic acid effectively corresponds to the compound of
formula (V) wherein R is hydrogen and therefore
converts compo~nds of formula V directly to their 3-
carbamoyloxymethyl analogues.
3-Hydroxymethyl starting material for use in the
. process of this embodiment of the invention may be prepared
by, for example, the methods described in British Patent No.
1,121,308 and Belgian Patent No. 783~449.
- 16 ~
~CJ 4~L6
Any blocking group substituting the 4-carboxy
group of compounds of formula tlI) or (IV) is desirably a
group which may readily be split off at a later stage of a
reaction sequence and advantageously is a group containing
1-20 carbon atoms. Suitable blocked carboxyl groups are well
known in the art, a list of-representative groups being included
in our a:Eorementioned Belgian Patent No 783,449 ,~referred
blocked carboxyl groups lnclude aryl lower alkoxycarbonyl
groups such as ~-methoxybenzyloxycarbonyl, p-nitrobenzyloxy
carbonyl and diphenylmethoxycarbonyl; lower alkoxycarbonyl
groups such as t-butoxycarbonyl; and lower haloalkoxycarbonyl
groups such as 2,2,2-trichloroethoxycarbonyl. The carboxyl
blocking group may subsequently be removed by any of the
appropriate methods disclosed in the literature; thus7 for
example, acid or base catalysed hydrolysis is applicable
in many cases, as are enzymically-catalysed hydrolyses.
Where at the end of a given preparative sequence
a s.ulphoxide analogue of a compound of formula I is obtained,conversion to the corresponding sulphide may, for example,
be effected by reduction of the corresponding acyloxysulphonium
or alkyloxysulphonium salt prepared in situ by, for example,
_ 17 -
~4~ L6
reaction with 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 such as acetic acid, tetrahydrofuran, dioxan,
dimethylformamide or dimethylacetamide). The reaction
may be effected at a temperature of -20 to +50C.
The antibiotic compounds of formula (I) may be
- formulated for administration in any convenient way,
by analogy with other antibiotics, for example in the
form of pharmaceutical compositions comprising a compound
of formula I or a non-toxic salt,
biologically acceptable ester, l-oxide or sol~ate
thereo~ adapted for use in human or veterinary medicine
Such compositions may be presented for use in c~ ventional
manner with the aid of any necessary pharmaceutical
carriers or excipients.
- 18 -
L80~6
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 with added preservative. The
compositions may take such forms as suspensions,
solutions and emulsions in-oily or ~queous vehicles,
and may contain formulatorv 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.
For veterinary medicine the compositions may, for
example, be formulated as intramammary preparations in
either long acting or quick-release bases.
In gen~ral the compositions may contain from 0.1%
upwards, e.g. 0;1-99%, preferably from 10-60% of the
active material, depending on the method of administration.
Where the compositions comprise dosage units, each unit
will preferably contain 501500 mg of the active ingredient.
; 20 The dosage as employed for adult human treatment will
- 19 -
~C3 48(~L6
preferably range from 500 - 4000 mg per day, depending
on the route and frequency of administration
The compounds according to the invention may be
administered in combination with other compatible
therapeutic agents such as antibiotics, for example
penicillins, other cephalosporins or tetracyclines.
- 20 -
8~6
The following examples illustrate the invention.
All temperatures are in C. Meltlng polnts were
determined on a Kofler block.
~L~48~6
A) PREPARATION OF STARTING MATERIALS
Preparation 1
a) Diphenylmethyl (6R,7R)-7-(Thien-2-ylacetamido~-3-
trichloroacetylcarbamoyloxymethylceph-3-em-4-carboxylate.
Trichloroacetyl isocyanate (13.2 g, 70 mmole) was
added to a stirred suspension of diphenylmethyl (6R,7R)-
3-hydroxymethyl-7-Cthien~2-ylacetamido)ceph-3-em-4
carboxylate (26.0 g, 50 mmole) in anhydrous acetone (600 ml)
at 20. The solid soon dissolved and after the mixture
had been stirred at 20 for 1 hour it was chilled for 1
hour and the resulting solid was filtered off and washed
with ether to give the title compound (33.1 g, 93%),
183 to 184; [~21 + 24 (c 0. 95 in DMS0); Ainf
235 nm (~ 14,500) and ~in~ 256 nm (E 8,820).
IR, NMR and microanalytical data confirmed the
structure as that of the title compound.
b~ Diphenylmethyl (6R,7R)-?-Amino-3-trichloroacetyl-
carbamoy_oxymethylceph-3-em-4-carboxylate _ ue~
sulphonic Acid Sal_.
Anhydrous pyridine (31ml9 0.384 mole) was added
to a solution of phosphorus pentachloride (20 g, 96 mmole)
in dry dichloromethane (300 ml)
- 22 ~
~48~16
at 3. The suspension was stirred for 10 minutes at 3
and diphenylmethyl (6R,7R)-7-(thien-2-ylacetamido)-3-
trichloroacetylcarbamoyloxymethylceph-3-em-4-carbox~rlate
(22.5 g, 32 mmole) was added; the reaction was stirred
at c 2 for 1 hour. The dark solution was poured
slowly into à cold (0) anhydrous mixture of methanol
(80 ml) and dichloromethane (200 ml~ with the
temperature kept below 5. The temperature of
the solution was then allowed to rise to 23 and, after
stirring the solution at this temperature for 1 hour,
water (200 ml) was added. The organic layer was separated
and washed with 2N-sulphuric acid, water, sodium bicarbonate
solution and water, dried over magnesium sulphate, and
evaporated in vacuoO The resulting oil was dissolved in
ethyl acetate and a solution of toluene-~-sulphonic acid
monohydrate (6.0 g, 31.5 mmole) in ethyl acetate was- added.
The combined solutions (ca. 350 ml) were poured into diethyl
ether (ca. 1 litre) and the resulting solid was filtered
off and dried in vacuo to give the title compound
(17.2 g, 72~/~), m.p. 150 to 153; [a~D + 7 5 (c 0.82 in
DMS0); AmaX 263 nm ( 7,600) and ~'inf 267 nm (E 7,350).
- 23 -
~ ~ 80 ~
IR, NMR and microanalytical data confirmed the structure
as that of the title compound.
Evaporation of the filtrate and trituration of
the residue with ethanol afforded unchanged starting
material (3.2 g, 14.2~
c) Diphenylmeth~ R~7R 7-~mino-3-carbamoyloxymethyl-
The toluene-~-sulphonic acid salt of diphenylmethyl
(6R,7R)-7-amino-3-trichloroacetylcarbamoyloxymethylceph-3-
em-4-carboxylate (17.2g9 22.7 mmole)was dissolved in a
mixture of anhydrous methanol (900 ml) and acetyl chloride
(45 ml) and left to stand at 20 for 5 hours. Removal
of the solvent under reduced pressure gave an oil, which
was dissolved in dichloromethane. This solution was
shaken with aqueous sodium bicarbonate solution and then
washed with water. Toluene-~-sulphonic acid monohydrate
(~.3 g, 22.7'mmole) was added and the solvent was evaporated
in-vacuo. The residue was dissolved in hot isopropanol
(ca, 150 ml) and the solution was poured into diisopropyl
ether (ca 600 ml), The precipitated solid was filtered
~ 24
~IL0~8~
off and dried in vacu~ to give the title compound
(8.9 g, 64%), m.p. 110 to 112; [a]21 -14 (c 1 0 i
CHC13); ~maX 259 nm (E 6,120) and ~lnf 227 nm (e 15,800).
IR, NMR and microanalytical data confirmed the
structure as that of the title compound.
Preparation 2
Di ~ bamoyloxymethylceph-3-
em-4-carboxylate_Toluene-p ~ lphonic Acid Salt
A stirred suspension of phosphorus pentachloride (156 g,
0.75 mole) in dry dichloromethane (1.5 litres) was cooled
in an ice-bath and treated with pyridine (60.5 ml, 0.75 mole)
at such a rate that the temperature of the mixture remained at
ca. 20 to 25. The mixture was stirred and cooled to 8 ~nd
diphenylmethyl (6R,7R)-7-(thien-2-yl)acetamido-3-trichloroacetyl-
carbamoyloxymethylceph 3-em-4-carboxylate (354.5 g,0.5 mole)
was added in portions over 10 minutes. The mixture was stirred
at ca. 8 or 1.75 hours and then added over 10 minutes to a
stirred mixture of butane-1,3-diol (225 ml, 2.5 mole) and
dichloromethane (500 ml) precooled to -20 so that the tem-
perature of the mixture was kept in the range -15 to -20.
.
_ 25
104801G
The cooling b~th was removed and the mixture was stirred at ca.
-10 for 20 minutes. Water (1 litre) was added and the two-
phase mixture was stirred for 30 minutes. The aqueous phase
was extracted with dichloromethane (2x500 ml), and the organic
phases were washed sequentiaIly with 2N hydrochloric acid (1 litre)
combined and evaporated to a brown gum. The gum was dissolved
in methanoL (3.6 litres) and this solution was stirred and
treated with saturated aqueous sodium hydrogen carbonate solution
(1.2 litre~ over a period of 10 minutes. The mixture was
stirred at ca. 20 for 1.5 hours and a small quantity of brown
solid was removed by filtration. The yellow filtrate was
concentrated in vacuo (bath temp. not greater than 40) to ca
1.5 litres and water (1.5 litres) was added. The resulting
suspension was refrigerated for 1 hour, and the yellow solid
was filtered off, washed well wlth water, sucked as dry as
possible and dried in vacuo at 40 for 24 hours. The greasy solid
th~s obtained, fo~lowed by toluene-p-sulphonic acid monohydrate
(81 g, 0 425 mole), were added to stirred chloroform (2 litres).
After several minutes the toluene-p-sulphonic acid salt
20 - began to crystallise~ Stirring was continued for a further
30 minutes, after which the water was removed azeotropically
- 26
10480~6
in vacuo with continuous replacement of the chloroform so as
.. . .
to maintain a volume of 2 litres. The suspension was re-
rigerated overnight and the product was filtered off, slurry
washed with chloroform (2x250 ml), refiltered, washed by
displacement wi~h chloroform (250 ml) and dried in vacuo at
40 to give the title oompou~d as an off-white crystalline
~ solid (237.. 8 g, 74 1%); ~m (EtOH) 262 nm ( 7,250); the
NMR spectrum (Me2SO-d6) indicated the presence of O.25
mole of chloroform.
o J Preparation 3
(6R,7R2-7-Amino-3-carbamoyloxvmethylceph-3-em-4-carbox~].ic Acid
Diphenylmethyl (6R,7R)-7~amino-3-carbamoyloxymethylceph-3
em-4-carboxylate toluene-p-sulphonic acid salt (300.0 g,
0.44 mole), solvated with ca. 0.6 mole of chloroform, was
added in portions over 30 minutes to a stirred mixture ~
trifluoroacetic acid (300 ml) and anisole (300 ml) immersed
in a water-bath at 20. The temperature of the mixture
rose from 23 to 28.over the first 20 minutes but fell back
to 26 by the end of the addition. The golden yellow solution
was stirred for 1 hour, the temperature falling to 21, and
- 27
~0~81D~6
was then added to a stirred mixture of ethyl acetate (1.5 litres)
and water (l.S litres) immersed in an ice-bath. The pH of the
stirred mixture was adjusted to 3~8 over 10 minutes with
ammonia solution (S G. 0.880), the temperature rising to 38.
The suspension was stirred and cooled to 10 over 1.25 hours
and filtered. The cream soiid was washed with water (750 ml)
and ethyl acetate (4 x 200 ml) and dried in vacuo to give the
(115.6 g, 96.2%); ~ (pH6 phosphate) 265nm
max
(7,750); purity by HPL (high pressure liquid chromatography)
99.7%.
Microanalytical data confirmed the structure as that
of the title compound.
Example 1
(6R,7R~-3-Carbamoyloxymet~ 7-C2-methoxyimillo-2-(thien-
2-yl)acetamido~ceph-3-em-4-carboxylic Acld ~n isomer`j
A mixture of N,N-dimethylacetamide (10 ml); acetonitrile
(10 ml), triethylamine (2.8 ml, 20 mmole), (6R,7R)-7-amino-3
carbamoyloxymethyl-ceph-3-em-4-carboxylic acid (1.09 g, 4 mmole)
q~7d ~a~4r ~/o ,~,
was stirred at oo for 90 minutes 5 the solid slowly dissolving~
Meanwhile a solution of phosphorus pentachloride (1.0 g, 4.8
^ - 28 -
1~ ~ 8~ ~ 6
4,8 mmole) in dry dichloromethane (12 ml~ was cooled
to oo, and N, N~dimethylacetamide (2 ml) was added,
The resulting solution was recooled to -10 and sodium
2-methoxyimino-2-(thien-2-yl)acetate (syn isomer) (923 mg,
4.8 mmole) was added The mixture was stirred at
-10 for 15 minutes and crushed ice (3 g) was added
The mixture ~was stirred at oo for 10 minutes, whereafter
the lower dichloromethane phase was added over 10 minutes
to the cephalosporin solution prepared above, cooled to
-10 so that the reaction temperature rose steadily to
0 The mixture was stirred at 0 to 2 for 1 hour
2N-Hydrochloric acid (50 ml) was then added and after
shaking the mixture a solid separated. The solid was
filtered, washed and dried in vacuo to give the title
compound (888 mg, 50%)
Its properties are: m p 157 to 163, ~~20 +57 3O
(c 1.0 in dioxan), RpAC 0 8* Solvent system A*, ~max
(pH6 buffer) 262 5 nm (~ 15,550), and inflexion at 235
nm (s10,350~ (DMS0-d6) 0 20 (d.J 8 Hz, NH), 2 29
(dd J 2 and 5 Hz, thienyl C5-H), 2.7 to 2.9 (m, thienyl
C3-H and C4-H), 3 40 (s CONH2),4 13 (dd, J 5 and 8 Hz.
C7-H), 4 75 (d J 5Hz, C6-H), 5 01 and 5.34 (AB-q. J 13
Hz, C3-CH~),6.08 (s.NOCH3),and 6 42 (collapsed
- 29 -
~L04~
Ab-q, C2~H2) Ymax (Nujol) 3700 to 2100 ~CO2H), 3480, 3440, 3365, and
3255 ~NH and NH2), 1760 (azetidin-2-one), 1722 (CO2H), 1709 ~OCONH2) and
1652 and 1530 cm 1 (amide). *See "Notes" after Table 1.
The title compound may also be prepared by treating acetone
(750 ml) at 0 with trichloroacetyl isocyanate (240 mmole), recooling the
solution to 0, and adding (6R,7R)-7-[2-methoxyimino-2-(thien-2-yl)acet-
amido]-3-hydroxymethylceph-3-em-4-carboxylic acid (syn isomer) (120 mmole)
in portions over 5 minutes with stirring so that the reaction temperature
does not exceed 6. The solution is then stirred for a further 15 minutes
and methanol (4.5 ml) added. The solution is concentrated to 60 ml and
the concentrate dissolved in methanol (750 ml). Sodium bicarbonate (540
mmole) in water (600 ml) is then added, followed by activated charcoal (4.5
g), and the resulting suspension is stirred at room temperature for 2 hours.
The charcoal is removed by filtration through Keiselguhr and the light yellow
filtrate is adjusted to pH 4.5 by the addition of dilute hydrochloric acid.
The solution is concentrated to half volume under reduced pressure and an
equal volume of water is added. The pH is adjusted to 2.0 with dilute hydro-
chloric acid and the product is isolated by filtration, washed with water (3
x 150 ml) and dried at 40 for 16 hours in vacuo to give the title compound.
In an al~ernative procedure, a slurry of (6R,7R)-7-[2-methoxy-
imino-2-(thien-2-yl)acetamido]-3-hydroxymethylceph-3-em-4-carboxylic acid
(syn isomer) (120 mmole) in dichloromethane (70 ml)/tetrahydrofuran (25 ml)
-
at 5 is trea~ed with dichloroacetyl isocyanate (25 mmole). The reaction
mixture is then treated as above to give the title compound.
In yet another procedure, a slurry of (6R,7R)-7-[2-methoxyimino-2-
(thien-2-yl)acetamido]-3-hydroxymethylceph-3-em-4-carboxylic acid (syn isomer)
(50 mmole) in dry acetonitrile (250 ml) is treated at between 5 and 10 with
chlorosulfonyl isocyanate (75 mmole) in acetonitrile (80 ml). The reaction
mixture is stirred at between 0 and 5 for 10 minutes and water (50 ml) is
added. The mixture is stirred at ca 20, and after 20 minutes a white
__
crystalline solid is separated. Evaporation and filtration gives the title
compound.
-
~ t - 30 -
10481DgL6
Examele 2
a) iphenylmeth~ (6R,7R)-3-Carbamoyloxymethyl-7- ~
(fur-2- ~ iminoacetamido~ceph-3-em-4-carboxylate_
(syn isomer~
A solution of DL-dicyclohexylcarbodiimide (7.75 g,
0.382 mole) in dry dichloromethane (50 ml) was added over
10 minutes to a solution o~ diphenylmethyl (6R,7R)-7-amino-3-
carbamoyloxymethylceph-3-em-4-carboxylate (13.7 g, 0.312 mole)
and 2-(fur-2-ylj-2-phenoxyiminoacetic acid (syn isomer)
(8.8 g, 0,382 mole) in dry dichloromethane (200 ml) at 0.
Ater 45 minute-s, a solid (presumably N,N'-dicyclohexyl
urea) was filtered o~f, and the filtrate was washed
with aqueous sodium bicarbonate solution and water, dried
over magnesium sulphate, and evaporated on a rotary evaporator
The residue was chromatographed on a Silica gel (lkg)
column. Less polar impurities than the reqired product
were eluted w1th dichloromethane (1 litre), acetone:
dichloromethane=2:98 (1 litr~, acetone:dichloromethane-
5 95 (L litres). gractions eluted with acetone: dichloro-
methane=10:90 and acetone:dichloromethane = 15:85 were
~048~ 6
evaporated to a gum (llg) which was triturated with
diethyl ether to give a solid (8.35 g, 41%). This was filt-
ered off and purified further by crystallisation from
aqueous ethanol to give the title com~und (7.6 g), m.p.
143 to 146, [a]22 ~ 48 (c l.0,.~Ie2S) ; ~max 273nm
( 18,700), ~i f 271 nm (17,600) and ~max 254 nm
(E16,5000).
.
IR, NMR and microanalytical data confirmed tha
structure as that of the title compound.
b) Sod um (6R,7R)-3-Carbamoyloxymethy~ -[2-(fur-2-yl)-
2-phenoxyiminoacetamidolceph-3-em-4-carboxYlate (syn isomer~
Trifluoroacetic acid (30 ml) was added over 10
minutes to an ice-cooled mixture of anisole (8 ml) and
diphenylmethyl (6R,7R)-3-carbamoyloxymethyl-7-[2-(fur-2-yl)
2-phenoxyiminoacetamido]ceph-3-em-4- carboxylate (syn
isomer) (7.4 g, 11.4 mmole). After a further 5 minutes at
- 32 - .
1~48~6
0, the dark solution was carefully poured into a mixture
of a saturated aqueous solution of sodium bicarbonate and
ether acetate. The aqueous solution was separated and
treated with activated charcoal. The ethyl acetate layer
was washed with water and the aqueous wash was combined with
the sodium bicarbonate extract and acidified with
concentrated hydrochloric acid. This acidic solution
was extracted with a mixture of ethyl acetate and diethyl
ether which was then;washed 5 times with water, dried over
magnesium sulphate, and evaporated in vacuo. The residue
was washed with diethyl ether and diisopropyl ether to
give the cephalosporin acid (4.5 g, 82%) as a solid.
This acid was dissolvedin ethyl acetate (150 ml)
and a solution of sodium 2-ethylhexanoate in ethyl acetate
(10 ml,containing lO mmole) was added. The solution was -
cooled in an ice-bath and stirred for 1.5 hours during
which time the product (2.84 g) crystallised out, lea~ing
unchanged acid (1.1 g was recovered by precipitation with
petrol b.p. 60 to 80) in solution. The solid was
filtered off to give the title compound
Physical constants for the title compound are
given in Table 1 hereinafter.
- 33 -
1~8~3~6
Example
a) Diphen~lmethyl(6R,7R)-3 C~rb~ ~ thyl-7~ y
imino-2-phe~y~acetamido)ce~-3-em-4-carboxylate (syn isomer)
Diphenylmethyl (6R,7R)-7-amino-3-carbamoyloxymethylceph-
3-em-4-carboxylate ~toluenesulphonic acid saLt (1.83g, 3mmole)
was added to a mixture of saturated aqueous sodium bicarbonate
solution (50ml) and dichloromethane (lOOml). The mixture was
shaken to dissolve the solid and the organic layer was separated,
washed with water (twice), dried ~er sodium sulphate, and
concentrated under reduced pressure to about 15ml. Thls
solution was cooled to 0 and solutions of D,L-dicyclohexyl~
carbodlimid2 (824mg,-4~nole) in dry dichloromethane (lOml) and
2-methoxyimino-2-phenylac2tic acid (~ isomer) (716mg, 4mmole)
in dry dichloromethane (lOml) were added. The~reaction
mixture was stirred at 0 for 70 minutes; it was then iltered,
washed with 2N-sulphuric acid, water, saturated aqueous sodium
bicarbonate solution, water and brine, dried over sodium
sulphate and evaporated to give a yellow solid (2.05g). ~nis
was dissolved in hot ethyl acetate (25ml), which was cooled
and dicyclohexyl urea was filtered off. Addition of diisopropyl
ether to the filtrate precipi ated a solid which was filtered
- 34 -
1~ ~8 ~ ~ 6
off, stirred and washed with diisopropyl ether, filtered,
and finally washed with diethyl ether to give the title
compound (1.10 g, 61.5%), m.p. 178-182; Ca]D +22.5
(c 1, CHC13)~ ~ 258.5 nm ( 18,500); ~ f 295 nm
( E 3,120).
IR, NMR and microanalytical data confirmed the
structure as that of the title compound.
b) (6R,7R~-3-Carbamoyloxymethyl-7-(2=methoxyimino-2-
E_en~lacetamido)ceph-3-em-4-carboxy~ic Acid (syn isomer)
Trifluoroacetic acid (4 ml) was added slowly to
a mixture of anisole (1 ml) and diphenylmethyl (6R,7R)-
3-carbamoyloxymethyl-7(2-methoxyimino-2-phenylacetamido)
ceph-3-em-4-carboxylate (syn isomer) (1.00 g, 1.66 mmole)
which had been cooled in an ice-bath. The reaction
mixture was stirred for the next 10 minutes The
flask wa~ then removed from the ice-bath and excess
trifluoroacetic acid was removed on a rotary evaporator.
Trituration of the residue withethyl acetate (10 ml),
filtration and washing with diethyl ether (25 ml and
10 ml) gave the title com~ nd (75%).
Physical constants for the title compound are
given in Table 1 hereinafter.
Example 4
a) DI;phenylmethyl (6R,7R)-3-Carbamoyloxymethyl-7-(2-
phenoxyimino-2-phenylacetamido)ceph-3-em-4-carbox-ylate
- 35 -
~09L8~6
(syn isomer~
The process of Example 3 (a) was repeated, except
that 2 phenoxyimino-2-phenylacetic acid (syn isomer) was
used in place of the 2-methoxyimino-2-phenylacetic acid
(syn isomer), to give a red sticky foam. This crude
product was crystallised from aqueous acetone to give a
red solld (1.3 g) which was washed t~lice (with stirring)
with diethyl ether to give the title come~nd (675 mg,
34%) m.p. 138-140; [a]D ~ 44-5 (c 1, CHC13); ~EtOH
264 nm (~ 1~7,400); ~inOH 268 and 281 nm (E ]6,850 and
14,000) as a white solid. The residu~ obtained after
evaporating the mother liquors and washings was
crystallised from ethanol to give further title compound
~; (431 mg, 17%~ in two crops, which were washed with diethyl ether with stirring.
~R, NMR and microanalytical data confirmed the
structure as that of the title compound.
b) Sodium.(6R,7R)-3-Carbamo~loxymethvl-7-(2-phenoxyimino
-2-phenylacetamido)ceph-3-em-4-carboxylate (s~n isomer)
Treatment of the product of (a) above in accordance
- - with ~he method of Example 3 (b) gave the crude cephalosporin
- 36 -
1~4~
acid, which was stirred with ethyl acetate and saturated
aqueous sodi~ bicarbonate solutlon. The resulting precipitate
was filtered off and washed with acetone and ether to give
' ~ , Tl
the title compound (66%), having the physical constants shown
in Table 1 hereinafter.
Example 5
a) Di~henylmethy~ (6R,7R~-3-Carbamo~loxymethyl-7-[2-
cyclopentyloxyimino-2-(fur-2-yl)-acetamido~_eph-3-em-4-
carboxylate (s~n isomer)
The process of Example 3 (a) was repeated, except
that 2-cyclopentyloxyimino-2-(fur-2-yl)acetic acid (syn
isomer) was used in place of the 2-methoxyimino-2-phenylacetic
acid (syn isomer) to give a foam (1.77 g), which was
triturated with ethyl acetate to give the title compound
(1.30 g, 67%), m.p. 102-108; [a]D + 12.5 (c 1, CHC13);
AmaXH 278 nm ( E 16,650~, as a pale~yellow solid.
b) ~R,7R)-3-Carbamoyloxy__thyl-7-L2-cyclopentyloxi-mino-2
(fur-2-yl)acetam _ Jceph-3-em-4-carboxylic Acid (syn isomer)
Treatment of the product of (a) above in accordance
with the method of Example 3 (b) gave the crude cephalosporin
acid, which was precipitated from ethyl acetate with diisopropyl
- 37 -
~ . .
~48~16
ether to give the title compound (55%), having the physical
constants shown in Table l hereinafter.
Example 6
a) Diphenylmethyl (6R,7R)-3-Carbamoyloxymethyl-7-(2-
ethoxyimino-2-phenylac_tamido)ceph-3-em-4-carboxylate
(syn isomer)
The process of Example 3 (a) was repeated D except
that 2-ethoxyimino-2-phenylacetic acid (syn isomer) was
used in place of the 2 methoxyimino-2-phenylacetic acid
(syn isomer). Crystallisation of the crude product from
methanol gave the title compound (l.30 g, 53%) in three
crops, m.p. 199-202; [a]D ~ 9 7 (c 1, dioxan);
~EtOH 259 nm (~ 20,000); AEinfH 295 nm (f 3,700 ).
b) (6R~ 3-Carbamoyloxymeth ~
phenylacetamido)ceph-3-em-4-carboxylic Acid (syn isomer)
. .
~reatment of the product of (a) above in accordance
with the method of Example 3(b) gave the crude cephalosporin
acid, which was triturated with ethyl acetate (3 ml),
filtered off~ and washed (with stirring) with ethyl acetate
(5 ml) and then diethyl ether (2x10 ml) to give the
title com~_und as a white solid (413 mg, 64%). A further
- 38 -
quantity (180 mg, 27%) crystallised from the filtrates
and was filtered off, and washed with diethyl ether.
Physical constants for the title compound are shown in
Table 1 hereinafter.
Example _ 7
.
a) Diphenylmethyl (6R,7R)-3-Carbamoyloxymethyl-7-[2-t-
butoxyimino-2-(thien-2-yl)-acetamido]ceph-3-em-4-carboxylate
~ .
The process of Example 3 ~a) was repeated, except
that 2-t butoxyimino-2-(thien-2-yl)acetic acid (syn isomer)
was used in place of the 2-methoxyimino-2-phenylacetic
acid (syn isomer). The crude product was purified by
stirring a suspension in diisopropyl ether (2x25 ml) to give
the title compound as a pale-pink solid ~1.90 g9 73%), m.p.
148-152; [~]D + 8.5 (c 1, CHC13); AEtOH 262 and 282 nm
(f 14,500 and 13,200).
b) Sodium (6R,7R)-3-Carbamoyloxymeth~l1-?-[2-t-butoxyimino-
2-(thien-2-yl)acetamidolceE~-3-em-4-carbox~ate (syn_isomer)
Treatment of the product of (a) above in accordance
with the method of Example 3(b) gave the cephalosporin acid
as a gum which solidified when triturated with diisopropyl
- 39 -
-
ether to give a crude product (1.20 g, 94%~. A portion of
this acid (811 mg, 1.68 mmole) and sodium 2-ethylhexanoate
(282 mg, 1.68 mmole) were stirred in n-butanol (5 ml) at
20 for 10 minutes and at 0 for 20 minutes. The
resulting yellow solid was filtered off and washed with
cold n-butanol (3 ml) and-diisopropyl ether (7 ml) to give
the title compound (495 mg, 58%), having the physical
constants shown in Table 1 bereinafter.
~
- 40 -
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~4~0~6
N~tes
.:
(1) RpaC = (Rf of compound)
(Rf of (6R,7R)-3-acetoxymethyl-7-
phenylacetamidoceph-3-em-4-carboxylic acid)
Solvent system (A) is n-butanol: ethanol: water
:: (4:1:5)
. ,
Solvent system (B) is n-propanol: water (7:3)
~ ~ .
(2) inf, denotes sn inflection
(3) Trifluoracetic acid spectrum - -
.
.~: , ^ '
- 44 -
