GB2197649A - 7-( alpha -(2-amino-4-thiazolyl)- alpha -oximino-acclamido)-cephem antibiotics - Google Patents

Description

it 1 CHEMICAL COMPOUNDS 2 19 7 GA 9 This invention relates to improvements

in or relatinq to cephalosporins. More particularly it relates to new cephalosporin compounds and derivatives thereof having valuable antibiotic activity.

The cephaiosporin 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.

Cepnalosporin 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 compounds, and in the treatment of Qenicillin-sensitive patients. In many instances it is desirable to employ a cephalosporin antibiotic which exhibits activity against both Gram-positive and Gram-neQative microorganisms, and a siqnificant amount of research has been directed to the development of various types of broad spectrum cephalosporin antibiotics.

Thus, for example, in our British Patent Specification No. 1399086, we describe 2 novel class of cephalosporin antibiotics containing a 7p-(aetherified oxyimino)acylamido side chain, the oxyimino group having the syn configuration. This class of antibiotic compounds is characterised by high antibacterial activity against a range of Gram-positive and Gramnegative organisms coupled with particularly high stability to Plactamases 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 aaainst particular classes of organisms, especially Gram-negative orqanisms. This interest is reflected in the very large numbers of patent applications which have been filed relating to cephalosporin antibiotics havinq particular substituents both on the 7p-acylamido side chain and at the 3-oosition of the cephalosporin nucleus.

For example, British Patent Specification No. 1576625 contains a generic definition of cephalosporin antibiotics havinQ a 7-((Xetherified oxy1mino, acetamido side chain wherein the etherifyinq qroup is an aliphatic hydrocarbon group which may have Suitable substituents

I includinq, amongst a large number of possibilities a carboxy or protected carboxy group and a phenyl group substituted by up to three nydroxy groups), which side Chain is further a-substituted by a group which inter alia may be an aminothiazolyl group. However none of the compounds specifically exemplified contains a carboxyphenyialkyi etnerifying group. The 3-position group may also be selected from a large number Of alternatives out a hydrogen atom is not included among these.

In British Patent Specification No. 1604971 a wide variety of cepnalosp3rin antibiotics are generally disclosed in which the 7Bposition side chain may be selected from inter alia a 2-(2-aminothi2zol-4yl,'-2-(etherified oxyimino',acetamido Qroup, in which the etherifyina group, amonast very many possible meanings, may be an alkvl group ( e.g. methyl'l substituted by both phenyl and carboxy, altriouah there is no specific exemplification of compounds havinq a carboxyphenylalkvl aroUP and the preferred etherifyino group is stated to oe an unsuostituted methyl arouQ. The 3-position Qroup may also be selected from 2 large number Of alternatives and possible 3-suostituents within the generic definition include 2 hydrogen atom.

In UK Patent Specification No. 2017702 the oxyimino etnerifyinq group, according to the generic definition, may inter alia be an 0:C2rt)oxypnenylmethyl radical. In the compounds specifically exemplified, the carboxyphenylmethyl group is always combined with an acetoxymetnyl group at the 3-position.

UK Patent Specification No. 2104888 generically discloses cephalosporin antibiotics in which the 7p-position side chain is a 2-(2- aminothiazol-4yl)-2-(etherified oxyimino)acetamido group. The oxy1mino etherifyinq group may inter 2lia be a carboxyphenylmethyl group in which the pnenyl QrouQ may be substituted by a hydroxy group. The 3-position group is an isothiazolylthiomethyl or iminoalkylidenedithiethane Qroup.

European Patent Specification No. 197409 qenerically discloses cephalosporin antibiotics in which the 7p-position side chain is a 2-(2aminothiazol-4-yl)-2-(etherified oxyimino) acetamido group. The oxyimino etherifyinq group may be inter alia a catechol carboxymethyloxyimino group. The 3-position substituent may be selected from a number of alternatives but these do not include a hydrogen atom.

We have now discovered that by the selection of a-(Z)-2-(2aminothiazol-4yl)-2-(etherified oxyimino)acetamido group at the 7p-position in combination with a hydrogen atom at the 3-position, and by the selection of a a-carboXy Substituted phenylmethoxyimino group as the etherified oxy1mino grouping, cephalosporin compounds having a particularly advantageous profile of activity (described in more detail below) against a wide range of commonly encountered pathogenic organisms and/or that are of use as intermediates in the preparation of other active compounds, may be obtained.

Accordingly, we provide cephalosporin compounds of the general formula (I), NHR 3 1 / % N H H Z -0. r-----CONH- = E/ \ N H hOR OCHCOOR2 0 1 \ 0 # \ R L+ 1 wherei R1 and R2, which may De the same or different, each represents a hydrogen atom or a carboxyl blocking group; R3 represents a hydrogen atom or an amino protectinq group; R4 and R5 each represents a hydroxy or substituted hydroxy group or R4 and R5 towther represent a cyclic protected diol group; 4 - Z is >S or >S-0 (a- or _ ; the dotted line bridQinq the 2-, 3-, and 4-positions indicates that the compound is a ceph-2-em or ceph-3-em compound; and non-toxic salts and solvates (especially hydrates) thereof.

In the compounds of formula (I), where R1 and/or R2 represent carboxyl blocking groups, the blocking group may be for example the residue of an ester-forming aliphatic or araliphatic alcohol or of an ester-forming phenol, silanol or stannanol (the said alcohol, phenol, silanol or stannanol preferably containing from 1 to 20 carbon atoms) or a symmetrical or mixed anhydride blocking group derived from an appropriate acid. Particular examples of R1 or R2 include t-butyl, diphenyImethyl and p-nitrobenzyl.

Where R3 is an amino protecting group, the protecting group may be for example a C7-20 aralkyl group (for example a triphenylmethyl or 4metnoxyDenzyl group , an acyl croup, such as an optionally substituted C1-6 alkanoyl group (for example a formyl or chloroacetyl group', or an optionally Substituted C1-6 alkoxycarbonyl group (for example a t-butoxycarbonyl or 2,2,2-trichloroethoxycarbonyl group), or a C7-10aralkyloxycarbonyl group (for example a benzyloxycarbonyl group'. or a silyl group (for example a tri-methylsilyl croup).

In qeneral, compounds of formula (I) in which R3'is a Invdroqen atom are preferred.

When R4 or R5 represents a substituted hydroxy croup it may be for example an acyloxy croup [e.g. a formyloxy group or a group of formula - OCOR6 (where R6 is a Cl-8 alkyl group, For example a methyl group.' 1, a carbonate group -OCO2R6 f where R6 is as defined above), a silyloxy group [for example a (C1-4-alkyl, silyloxy group such as a trimethylsilyloxy or a t-butyldimethylsilyloxy group], or a borate [-OB(OR7)21 or phosphate [-OP(O)(OR71 group (where R7 represents 23 C1-4 alkyll'.

Where R4 and RS together form a cyclic protected diol grouping, this may ne an alkylidenedioxy group, preferably having 1-20 carbon atoms, e.g. a methylenedioxy, ethylenedioxy or isopropylideneoioxy group which may carry one or more suostituents e.g. phenyl, Cl-4-alkoxy, or oxo substituents, for example methoxymethylenedioxy, cllpnenylmethylenedioxy or carbonyldioxy groups; a cyclic borate group, for example -OB(OH)O-; a cyclic phosphate group, for example -OP(O)I,OH)O-, or -OP(O)(OR7)0 7 is as defined above or a - (where R cyclic silyl ether group, e.g. a di(CI-4alkyl)silyldioxy group for example a dimethylsilyldioxy group.

In general, such silyloxy, borate or phosphate groups represent protected hydroxy groups which may be cleaved to provide a compound of formula (1) havinq free hydroxyl qroups.

In general, R4 and R5 is each preferably an acetoxy group or in particular a hydroxy group.

In the compounds of formula (I), Z is preferably >S.

Ceph-3-em compounds of the invention are particularly preferred.

Where the compound is to be used in medicine any ester of the carooxyl groups in the molecule should oe a non-toxic metabolically labile ester function. Examples of non-toxic metabolically labile ester derivatives include acyloxyalkyl esters, for example, lower alkanoyloxy-methyi or ethyl esters such as acetoxy-methyl or -ethyl or pivaloyloxymethyl esters, and alkoxycarbonyloxyethyl esters, for example, lower aikoxycarbonyloxyethyl esters such as the ethoxycarbonyloxyethyl ester.

In addition to the above ester derivatives, it will be understood that the present invention includes within its scope the active compounds of the invention in the form of other physiologically acceptable equivalents, i.e. physiologically acceptable compounds which like the metabolically labile esters are converted in vivo into the parent antibiotic compounds of the invention.

Non-toxic salt derivatives which may be formed by reaction of the carboxyl group present in the compounds of 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, phenylethylbenzyiamine, dibenzylethylenediamine, ethanoiamine, diethanolamine and N-methylglucosamine salts). Other non-toxic salt derivatives include acid addition salts, e.g. formed with hydrochloric, hydrobromic, sulphuric, nitric, phosphoric, formic and trifluoroacetic acids. The salts may also be in the form of - (D - resinates formeo with, for example, a polystyrene resin or crosslinked polystyrene divinylDenzene copolymer resin containing amino or quaternary amino groups or sulphonic acid groups, or with a resin containing carboxyl groups, e.g. a polyacrylic acid resin. Soluble base salts (e.g. alkali metal salts such as the sodium salt) of the compounds of formula (I) may be readily used in therapeutic aoplications 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 application, e. g. for use in depot preparations, such salts may be formed in conventional manner, for example with appropriate organic amines.

The compounds according to the invention are ln isomers. The syn isomeric form is defined by the configuration of the -OCHCOOR2 R4 5 group with respect to the carooxamido group. In this specification, the svn configuration is denoted structurally as:

NHR3 S N r ONH- 11 N OCHCOOR2 # R4 7 35.

It will be understood that since the compounds according to the invention are geometric isomers, some admixture with the corresponding anti isomer may occur.

It will further be appreciated that in the oxime etherifying group, the carbon atom adjacent to the oxy group is chiral and may therefore exist in either the R or S configuration. The invention thus includes within its scope the individual R and S forms at this chiral carbon atom as well as mixtures (including diastereomeric mixtures) thereof. In general, compounds of formula (I) in which this chiral carbon atom has the Sconfiquration and R/S mixtures in which the S-isomer predominates are preferred.

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.

As indicated previously, the compounds of the invention are active against a wide range of commonly encountered pathogenic organisms and/or are of use as intermediates for the preparation of other active compounds. In general, when the compounds of the invention are to be used as intermediates the groups R1 and R2 will often be carboxyl blocking groups; the group R3 will often be an amino protecting group, and the groups R4 and R5 will often be protected hydroxy groups such as SilyloXy, borate or phosphate groups, or together will be a cyclic protected diol group. Nontoxic derivatives wherein R4 and/or R5 represent acyloxy groups such as acetoxy groups may serve as either intermediates or as active compounds.

In general, active compounds of the invention will be ceph-3-em compounds of formula (I) in which R1, R2 and R3 represent hydrogen atoms,Z represents >S and R4 and 0 which may be the same or different represent hydroxy- or CI-C4 acYlOxy groups e.g. acetoxy groups.

Important active compounds according to the invention have the formula (Ia) - 8 NH i 2 0 / 111\ S N 1 1 H H S E/ \ H N 1 1 0 0 a H 60H CHCOOH la.' wherein R4a is a hydroxy or acetoxy group; R5a is a hydroxy or acetoxy group; and the non-toxic salts, solvates, hydrates and metabolically labile esters thereof.

A particularly preferred compound of the invention is: 6R,7R,2'Z,SI-7-[2'%2-aminothiazol-4-vll/-2-[(carboxv)(3,4-dlhydroxypten,, I'Ymetnoxviminolacetamiciolceph-3-em-4-cart)oxylic acid; and the nontoxic salts, solvates, hydrates and metaoolically laoile esters tnereof.

We nave discovered that l6R,7R,2'Z,S,-7-[2-'2-aminotrilazol4-vl)-?2-['C2rooxv"'3 -dihydroxvphenyl,'methoxyiminolacetamidolcepn-3y% 14 em-4-carr)oxyiic acid can advantageously and consistently be prepared and isolated with a high degree of purity in crystalline form and th forms a further aspect of the invention. In particular we have prepared and isolated crystalline hydrated (6R,7R,2'Z,S)-7-[2-'k2aminothiazol-4yl''-2-['carboxy)3,4-dihydroxyphenyl Ymethoxyiminolacetamidolceph-3-em-4carboxylic acid. This new material is superior not only in its crystallinity and increased purity but is also obtained in high yields and has increased stability on storaqe even at a high temperature over extended periods. These properties of the crystalline material render it of particular value in pharmaceutical is use.

The above hydrated crystalline material may be characterised by the infrared spectrum and/or by its x-ray powder diffraction pattern. IR Spectrum (Nujol) v max 3700-2100 (broad), 1760, 1720, 1660, 1555, 1520, 1350, 1300, 1290, 1240, 1215, 1170, 1155, 1120, 1030, 1000, 920, 860 and 755cm- X-ray Diffraction Pattern (given as d spacings in Angstrdm units and percentage intensities I). 12.5 (21); 9.97 (37); 9.51 (22); 6.79 (11); 6. 33 (35); 5.29 (10); 4.76 (30); 4.63 (100); 4.39 (54); 4.32 (5); 4.18 (15); 4.09 (31); 3.91 21); 3.42 (6); k24); 3.78 (69); 3.69 (17); 3.61 (9); 3.52 (12); 3.48 ' 3.33 (37); 3.15 (36); 3.07 (22); 3.02 (4); 2.96 (36); 2.85 (9); 2.78 (3); 2.75 (3); 2.65 (11); 2.59 (49); 2.50 (6); 2.44 (9); 2.38 (6); 2.31 (3); 2.27 IW; 2.20 (5); 2.16 (9); 2.10 (10); 2.05 (4); 2.01 (9).

Compounds according to the invention exhibit broad spectrum antibiotic activity aqainst both Gram-positive and Gram-neqative orqanisms, including many P-lactamase producinq strains. The compounds also possess high stability to P-lactamases produced by a range of Gram- neqative and Gram-positive orqanisms.

Compounds acccording to the invention have been found to exhibit hiQh activity against strains (including penicillinaseproducing strains) of Gram-positive bacteria such as Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus species. This is coupled with excellent activity against PseUdomonas species, and also with high activity against various members of the Enterobacteriaceae (e.g. strains of Escherichia coli, KlebSiella pneumoniae, Enterobacter cloacae, Serr2ti2 marcescens, Proteus mir2bilis and indole-positive Proteus organisms such as Proteus vulgaris, Proteus morganii and Providence species), and strains of Haemophilus influenzae and Acinetobacter calcoaceticus. This Combination of hiah activity against Gram-positive organisms with high activity 2Qainst Gram-negative organisms, more particularly against Pseudomonas, that is possessed by the compounds of the invention is unusual and particularly advantageous.

Cephalosporin derivatives described herein have been found to possess a desirable long serum elimination half life in vivo.

Compounds of the invention may be used for treating a variety of diseases caused by pathogenic bacteria in human beings and animals, such as respiratory tract infections and urinary tract infections.

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 for 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 muiti-dose containers, if necessary with an added preservative. The compositions may also take such forms as suspensions, solutions, or emulsions in oily or aoueous vehicles, and may contain formulatory agents such as suspending, stabilisinq 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 physiologically acceptable. Alternatively the base may be present in the water with wnicIn the powder is reconstituted. The base may be, for example, an inorganic base such as sodium carbonate, sodium bicarbonate or sodium acetate, or an organic base such as lysine or lysine acetate.

The composition may also be presented in a form suitable for absorption by the qastro-intestinal tract, for example, tablets, capsules, syrups or suspensions for oral adminstr2tion, and suppositories.

Compositions for veterinary medicine may, for example, be formulated as intramammary preparations in either long actinq or quick-release bases.

The compositions may contain from 0.1'0 upwards, e.g. 0.1-99% of the active material, depending on the method of administration. When the compositions comprise dosage units, each unit will preferably contain 1003000 mg of the active ingredient e.g. 200-2000 mg. The daily dosage for adult human treatment will preferably range from 200 to 12000 mg e.g. 1000-9000 mg per day, depending inter alia on the nature of the infection and the route and frequency of administration. In general, intravenous or intramuscular administration will be employed, for example using 400 to 4000 mg per day of the active ingredient in adult human treatment. It will be appreciated that in some circumstances, for example, in the treatment of neonates, smaller dosage units and daily dosages may be desirable.

The antibiotic compounds according to the invention may be administered in combination with other therapeutic agents such as antibiotics, for example penicillins, cephalosporins or other 5-lactam compounds.

The compounds of the invention may be prepared by a number of processes, discussed below.

Thus, according to another embodiment of the invention we provide for the preparation of an antibiotic compound of general formuia (1) as hereinbefore defined or a non-toxic salt, solvate or hydrate thereof by acylating a compound of the formula (II) H H Z E/ \ H2N H COOR (I I) (wherein 0, Z and the dotted line are as defined for general formula (I)) or a salt, 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 methanesulphonic or - 12 toluene-p-sulphonic acid, of a 7N-silyl derivative thereof, with an acid of formula (III,' NHR 3 1 0 N 1 i =-C. COOH 11 N \ OHCOOR2 j ', 6 0 \ Y 0 R 4 1 (III) 1 2 3 4 5 %wherein R, R, R and R are as defined above) or a salt thereof, or with an acylating agent corresponding thereto; 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 A2_isomer into 2 desired A3_isomer, reduction of a compound wherein Z is >5-O to form a compound wnerein Z is >S, conversion of a carboxyl aroup into a non-toxic metabolically laoile ester function, formation of a non-toxic salt or solvate, removal or any carooxyl blockinQ and/or N-protecting groups, and removal of any nydroxy Dlocking groups. The aoove reactions i) to vi) may be carried out in conventional manner. In tne acylation process, the starting material of formula (II) is preferably a compound wherein Z is >S and the dotted line represents a ceph-3-em compound. Acylatinq agents which may De employed in the preparation of compounds of formula (1) include acid halides, particularly acid chlorides or bromides. Such acylatinq agents may be prepared by 1 i) v i 1, reacting an acid (III) or a salt thereof with a halogenating agent e.g. phosphorus oxychloride, thionyl chloride or oxalyl chloride.

Acylations employinq acid halides may be effected in aqueous and nonaqueous reaction media, conveniently at temperatures of from -50 to +500C, preferably -40 to +300C, if desired in the presence of an acid binding agent. Suitable reaction media include aqueous ketones such as aqueous acetone, aqueous alcohols such as aqueous ethanol, esters such as ethyl acetate, halogenated hydrocarbons such 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. triethyiamine or dimetriyianiline), inorganic oases (e.g. calcium carbonate or sodium oicaroonate), and oxiranes such as lower 1,2-alkylene oxides (e.g. ethylene oxide or propylene oxide) which bind hydrogen halide liberated in the acylation reaction.

Acids of formula (III) may themselves oe used as acylating agents in the preparation of compounds of formula (I). Acylations employing acids (III) are desirably conducted in the presence of a condensing agent, for example a carbodiimide such as N,NI-dicyclohexylcarbodiimide or N-ethylN'-y-dimethylaminopropylcarbodiimide; a caroonyl compound such as carbonyldiimidazole; or an isoxazolium salt such as N-ethyl-5phenylisoxazolium perchlorate; or N-ethoxycarbonyl2-ethoxy-1,2dihydroquinoline.

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.Q 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 suipnonic acids (for example toluene-p-sulphonic acia). An activated ester may conveniently be formed in situ using, for example, 1hyciroxyt)enzotriazole in the presence of a condensing agent as set out above. Alternatively, the activated ester may be preformed.

Acylation reactions involving the free acids or their abovementioned amide-forming derivatives are desirably effected in an anhydrous reaction medium, e.g. methylene chloride, tetrahydrofuran, dimethy1formamide, acetonitrile, dimethylacetamide or dimethyl Sulphoxide.

An alternative method Of activation is, for example, by reacting an acid of formula (III) with 2 solution or suspension preformed by adding a carbonyl halide, in particular oxalyl chloride or phosgene, or a phosphoryl halide such as phosphorus oxychloride to a solvent such as a halogenated hydrocarbon, for example methylene chloride, containing a lower acyl tertiary amide such as N,N-dimethy1formamide. The activated form of the acid of formula (III) may then be reacted with a 7-amino compound of formula f1l) in a suitable solvent or mixture of solvents for exampie halogenated hydrocarbons e.g. dichloromethane; alcohols such as an alkanol, e.g. ethanol or industrial methylated spirits; esters, e.g. ethyl acetate; ethers, e.g. tetrahydrofuran or dioxan; ketones, e.g. acetone; amides, e.g. dimethyl2cetamide; acetonitrile; water and mixtures thereof.

The acylation reaction may conveniently be effected at temperatures of from -500 to 500C, preferably -400 to +300C, if desired in the presence of an acid binding agent, for example as f described above e.Q. dimethylaniline, triethylamine or sodium oicarbonate.

If desired, the above acylation reactions M2y be carried out in the presence of a catalyst such as 4-dimethylaminopyridine.

The acids of formula (IIII/ and acylatino agents corresponding thereto may, if desired and where appropriate, be prepared and employed in the form of their acid addition salts. Thus, for example, acid chlorides may conveniently be employed as their hydrochloride salts, and acid bromides as their hydrooromide salts.

For use as starting materials for the preparation of compounds of general formula (I) according to the invention, compounds of general formula (III) and the amide forming derivatives thereof, such as acid halides and anhydrides corresponding thereto, are preferably used in their syn isomeric form or in the form of mixtures of the syn isomers and the corresponding anti isomers containing at least 9000 of the syn isomer.

- Acids of formula (III) an d their derivatives may be prepared by etherification of a compound of formula (IV) NHR 3 S N COOR8 N OH (IV) 3 wherein R is as hereinbefore defined and R8 represents a hydrogen atom or a carooxyl blocking group) or a salt thereof, by selective reaction with a compound of general formula (V) T.CHCOOR2 i \ 0 # \ R 4 1 R' 5 v) 1 wherein T is a chloro, bromo or iodo atom; a sulphate aroup; or a sulphonate group, such as tosylate), followed by removal of any carboxyl blocking group R8.

The etherification reaction is conveniently 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.

Separation of isomers May be effected either before or after such etherification. Under the conditions described above the configuration of the oxyimino group is substantially unchanged by the etherification reaction.

When the compound of formula (IV) is employed in the form of a free acid or a salt with a base, the etherification reaction is generally carried out in the presence of a strong base e.g. potassium t-outoxide, sufficient base being added to form a dianion. Furthermore, the reaction should be effected in the presence of a base - 1 ts - if an acid addition salt of a compound of formula (IV) is used, the amount of Dase oeing sufficient to neutralise rapidly the acid in question.

Acids of formula (III) may also be prepared by reaction of a compound of formula (VI) NHR3 8 CO.COOR (V I) 3 8 wherein R and R are as hereinbefore defined) with a compound of formula (VII) H2N.O.YHCOOR R 4 5 1,v I I I 2 4 5 wherein R I R and R are as hereinoefore defined) followed by removal of any carooxyi Dlocking group R8, and where necessary the separation of syn and anti isomers.

The reaction is conveniently carried out in a solvent such as di., nethylformamide, dimethylacetamide, dimethyl sulphoxide, tetrahydrofuran or methanol, all optionally in the presence of water, at a temperature of -200 to +500C, preferably 00 to 300C.

The acids of formula (III) may be converted into the corresponding acidhalides and anhydrides and acid addition salts by conventional methods, for example as described hereinabove.

Intermediates of formula (VII'/ May be prepared by treating compounds of formula (VIII) is j j5 Y.O.CHCOOR2 1 # R4 (VIII) (wherein Y is an imido group, for example a phthalimido, succinimido or maleimido group) with a hydrazine reagent such as hydrazine hydrate or an alkyl hydrazine such as methyl hydrazine. The reaction will generally be performed in an inert solvent, for example a haloqenated hydrocarbon such as methylene chloride at a low temperature, for example -700 to +300C.

Intermediates of formula (VIII) may be prepared by alkylation with compounds of formula (R) HalCHCOOR2 1 (IX) f wherein Hal is a haiogen atom such as a chlorine or bromine atom) of an appropriate N-hydroxyimide, (e.g. N-nydroxyphthalimide, Nhydroxysuccinimide or N-hydroxymaleimide) in the presence of a base such as triethylamine in a solvent such as acetonitrile at for example -100 to +300C.

Intermediates of formula (IX) are either known compounds or may be prepared using methods analogous to those used for the preparation of the known compounds Compounds of formula (II) used as starting materials in the acylation process are known from the literature e.g. British Patent Appiication No. 2159817 or can be prepared accordinq to information from the literature.

18 - A 2-cephalosporin ester derivative obtained in accordance with the above process of the invention may be converted into the corresponding desireo A3_clerivative by, for example, treatment of the A2-ester with a base, such as pyridine or triethylamine.

A cepn-2-em reaction product may also be oxidised to yield the corresponoing ceph-3-em 1-oxide, for example by reaction with a peracid, e.g. peracetic or m-chloroperbenzoic acid; the resulting sulphoxide may subsequently be reduced as described hereinafter to yield the corresponding desired ceph-3-em sulphide.

Where a compound is obtained in which Z is >S-bO this may be converted into the corresponding sulphide by, for example, reduction of the corresponding acyloxysulphonium or alkoxysulphonium salt prepared in situ by reaction with e.a. acetyl chloride in the case of an acetoxysulphonium salt, reduction being effected by, for example, sodium dithionite or bv iodide ion as in a solution of potassium iodide in a solvent e.g. acetic acid, acetone, tetrahydrofuran, dioxan, dimethylformamide or dimethylacetamide. The reaction may be effected at a temperature of from 200 to +500C.

In the oxidation and reduction processes described above, the groups R4 and RS in the starting materials are desirably other than M,,jrox,,1 groups.

MetaDolically laDile ester derivatives of the carDoxyl groups may De prepared by reacting a compound in the compounds of formula (I. of formula (1) or a salt or protected derivative thereof with the appropriate esterifying agent such as an acyloxyalkyl nalide or alkoxycarbonyloxyalkyl halide 'e.g. iodiae) conveniently in an inert organic solvent such as dimethylformamide or acetone, followed, where necessary, by removal of any protecting qroups.

Base salts of the compounds of formula (1) may be formed by reacting an acid of formula (I) with an appropriate base. Thus, for example, sodium or potassium salts may be prepared using the respective acetate, 2ethylhexanoate or hydroqen carbonate salt. Acid addition salts may be prepared by reacting a compound of formula (I) or a metanolically labile ester derivative thereof with the appropriate acid.

- 19 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.

It should be appreciated that in some of the above transformations it may be necessary to protect any sensitive groups in the molecule of the compound in question to avoid undesirable side reactions. Examples of suitable protecting groups are given in "Protective Groups in Organic Synthesis" by Theodora W. Greene (John Wiley and Sons, 1981).

For example, during any of the reaction sequences referred to above it may oe necessary to protect the NH2_group of the aminothiazolyl moiety, for example by tritylation, acylation (e.g. chloroacetylation or formylation), protonation or other conventional method. The protecting group may thereafter 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 optionaily halogenated carooxylic acid, e.g. acetic acid, formic acid, chloroacetiC acid or trifluoroacetic acid or using 2 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 treatment with thiourea.

Similarly, the hydroxy groups of the catechol moiety may need to be protected during any of the above reaction sequences. Hydroxy protectino qroups which may be removed under mild conditions will generally be suitable, for example acetyl or silyl groups. Such groups may be introduced in conventional manner and, when desired, removed such that breakdown of the product does not occur. For example in the case of an acetyl group the group may be removed by solvolysis with an aqueous solvent such as aqueous methanol or aqueous ethanol in the presence of a base for example sodium bicarbonate, ammonium hydroxide, ammonium caroonate or ammonium caroamate. A trimethyl silyl group may be cleaved, for example by treatment with a dilute aqueous acid.

Car0oxyl blocking groups used in the preparation of compounds of formula (I) or in the preparation of necessary starting materials are desiraoly groups which May readily oe Split Off at a suitable stage in the reaction sequence, conveniently at the last stage. It - M - may, however, be convenient in some instances to employ non-toxic met2boliC211Y labile cart)oxyl blocking groups such as 2CYlOXy-methyl or - etnyl groups '\,e.g. acetoxy-methyi 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 carooxyl groups being included in BritiSn Patent No. 1399086. Preferred blocked carnoxyl groups include aryl lower aikoxycarDonyi groups such as p-methoxynenzyloxycarbonyl, pnitronenzyloxycaroonyl and diphenylmethoxycarbonyl; lower alkoxycarDonyl groups sucri as t-butoxycarbonyl; and lower haloalkoxycarbonyi groups sucn as 2,2,2-trichloroetnoxycaroonyl. The carboxyl blocking group May subsequently be removed by any of the appropriate methods disclosed in the literature; thus, for example, acid catalysed hydrolysis or reduction is applicable in many cases, as is enzymically-catalysed hydrolysis.

Where a particular enantiomer of a compound of formula (1) is required St2rtino materials h2Vinq the desired stereochemical confiour2tion sriould be used in the above processes. Such intermediates may be obtained using conventional resolution processes. Tius for example enantiomeric intermediates of formula (VIII) wnerein R2 is a hydrogen atom in which the chiral carbon atom is in the (R) or 'S,' configuration may be obtained D reaction of a mixture of enantiomers with a resolving agent such as a chiral organic base [e.g. R-(+,'-a-metnyloenzylamine1 in a solvent such as acetone or acetonitrile to form the corresponding cliastereomeric salts. The salts may then be separated by known methods and the desired chiral intermediate of formula (VIII/I regenerated by treatment with an aqueous acid, e.g. aqueous hydrochloric acid, at for example room temperature.

The crystalline f6R,7R,2'Z,S,-7-[2-(2-aminothiazol4-yi,-2-[fcart)oxy)(3,4dihydroxyphenyi)methoxyimino]acetamido]ceph3-em-4-cart)oxyiic acid as its hydrate can conveniently be prepared from an aqueous solution of a salt of the above cephalosporin, or a solvate thereof.

Thus, according to a further embodiment of the invention we provide a process for preparing crystalline hydrated (6R,7R,2'Z,S)-7-[2-(2aminothiazol-4-yl)-2-E(carboxy)k'3,4methoxyiminolacetamido]ceph-3-em-4 dihydroxyphenyll -carboxylic acid by crystallising said acid from aqueous solution, preferably an aqueous solution of an acid addition or base salt thereof or a solvate of said salts, to form Said crystalline hydrated product. Crystallisation wilinormally be followed by isolating and drying the product.

Suitable base salts include, for example, inorganic base salts, such as alkali metal salts and alkaline earth metal salts, and organic base salts, as described above. A particularly suitable base salt is the sodium salt.

Starting acid addition salts may be formed with an organic or inorganic acid. Organic acids which may be used include carboxylic and sulphonic acids, for example, formic, trifluoroacetic and methanesulphonic acids. Inorganic acids which may be used include mineral acids, for example hydrochloric, hydrobromic or sulphuric acids.

According to a further aspect of the invention the desired material may be crystallised from a solution of an acid or base salt (3,4- of (6R,7R,2'Z,S,-7-E2-(2-aminothiazol-4yl)-2-[(carboxyl" dihydroxyphenyl)methoxyiminolacetamido]ceph-3-em-4-carboxylic acid, or a solvate thereof, in an aqueous medium by adjusting the pH to 1.0 to 4.0.

For example, a hydrate may be crystallised from an aqueous solution of a base salt on addition of an organic or inorganic acid to a pH in the above ranges. Suitable acids wh-ich may oe used in the crystallisation include, for example, hydrochloric acid and sulphuric acid. Alternatively, the desired hydrate may be crystallised from an aqueous solution of an acid addition salt by adding an organic or inorganic base to an appropriate pH in the above ranges. Bases which may be used include, for example, alkali or alkaline earth metal hydroxides, carbonates, bicarbonates or acetate, for example sodium hydroxide, sodium carbonate, sodium bicarbonate or sodium acetate.

- 22 The aqueous medium may contain a water-miscible organic solvent such as an alcohol, for example ethanol or isopropanol, an ether, for example tetrahydrofuran or dioxan, an amide, for example N,N-dimethylformamide or N,N-dimethylacetamide, a ketone, for example acetone, or a nitrile, for example acetonitrile.

The crystallisation is desirably effected at ambient temperature, for example from 00 to 300C, preferably from 15-250C. The crystalline product may be recovered by filtration and washed and dried in conventional manner, for example by air drying or by careful drying under reduced pressure.

The following Examples illustrate the invention. All temperatures are in OC. Nujol and Sorosil are trade marks. SorbSil U30 is silica gei manufactured by Joseph Crosfield and Son of Warrington, Cheshire, England. Unless otherwise stated NMR spectra were recorded in DMSO-d6, X-ray diffraction measurements were made on a Siemens D-500 diffractometer, using CuK= radiation. X-ray intensities were measured at 0.020 increments of 20 for 5 second intervals, using a scintillation counter, between values of 20 and 900. Results were stored on 2 computer for processing.

Intermediate 1 2-(3,4-Dioxvcarl)onvlphenyl)-2-(phthalimidooxy)acetic acid A solution of N-hydroxyphthalimide (14.6q) and triethylamine was added to a stirred suspension of 25m1, in acetonitrile (50ml,' 2-'3,4-dioxycarDonylphenyl)-2-chloroacetic acid (20.5g) in acetonitrile at -20 over 20 minutes. After a further hour at about 00, a solution of concentrated hydrochloric acid (7.5m1) in water (100m1) was added rapidly. Water (100m1) was added slowly and the initial oil lioerated crystallised, aided by seeding. The mixture was filtered and the filter-cake was washed witn water, and ethyl acetate: petroleum ether (DP 40-600) (1:2) and dried to give the title compound (30g), m.p. 183 to 1850; 8 5.84 (s, OCH), 7.53 (s, catechol 5-H and 6-H), 7.69 (s, catechol 2-H,, and 7.85 \s, prithalimido protons).

Intermediate 2 ka) W-(+)-a-Methylbenzylamine salt of (S)-2-(3,4dioxycart)onylphenyl)-2-(phthalimidooxy)acetic acid A solution of R,(+)-a-methylbenzylamine (16.3m1) in acetone (100m1) was added rapidly to a magnetically stirred solution of Intermediate 1 (45g) in acetone (1.25 litres at 210 under nitrogen. After 30 minutes the mixture was filtered and the precipitate was washed thoroughly with acetone to yield the title compound (16.57q); [a]21 + 2420 (c 1.07, EtOH); p 6 1.46 (d, J 7Hz, CH3CH), 5.48 (s, OCH), 7.3 to 7.6 (m, aromatic protons) and 7.80 (s, phthalimido protons).

(o) Diphenylmethyi (S)-2-(3,4-dioxycarbonylphenyl)-2-_fkphthalimidooxy) acetate 2M Hyarochioric acid (10ml) was added to a stirred suspension of Intermediate 2(a) (5.0g) in water (30mi) under nitrogen at 210. After 2 minutes, a solution of cliphenyldiazomethane containing one equivalent in metnylene chloride Olml, was added. After stirring vigorously for 35 minutes, the organic layer was separated and added dropwise to stirred ethanol f150ml). The mixture was stirred.at 210 for 10 minutes and then stored at 40 for 1 hour. The crystals were collected by filtration, washed with ethanol and dried to give the title compound (3.59Q), m.p. 135 to 135.50; [CX]21 + 112.60 (c 1.18, ethyl acetate).

D - Intermediate 3 (S)-(3,4Dihyciroxyphenyl)(diphenylmethoxycarbonyl)methoxyamine Intermediate 2(b) (5.71g) was stirred in methanol (390m1) with M- hydroChloric acid (5.5m1) at ca 400 for 4.5 hours. The solution was concentrated and mixed with methylene chloride. After washing twice with water, the solution was dried over magnesium Sulphate and evaporated to a foam. A solution of this foam in methylene chloride (176mi) was cooled to -500 with stirring under nitrogen and hydrazine hydrate (1.5m1) added. The mixture was allowed to warm slowly to 210 and stirred. After 5.75 hours the mixture was filtered anc the filter-cake was leached with methylene chloride. The combined 2.4 filtrates were diluted with ethyl acetate and washed with citric acid solution and brine. After drying over magnesiu-n sulphate, evaporation gave the title compound (4.35g) as a foam; [a]21 + 17.80 (c 1.03, methanol); D - 8 5.02 (s, OCHCO), 6.68 and 6.81 (m, thiazoleH, OCH and catechol protons, 7.1 to 7.4 (m, aromatic protons) 9.04 (s, OH).

Intermediate 4 (Z,S)-2-(2-Aminothiazol-4-yl)-2-[(3,4dihydroxphenl)(diphenZlmethoxycart)onyl)methoxyiminolacetic acid 2-(2-Aminothiazol-4-yl)qlyoxylic acid (1.91Q) was added over 3 minutes to a solution of Intermediate 3 (4.20g) in N,N-dimethylformamide f22ml, at 30 with stirring. After a further 30 minutes with ice-water cooling, the solution was allowed to warm to 210 over 1.5 hours and then added dropwise to an ice-water mixture (110g) with stirring for 20 minutes. The precipitate was collected by filtration, washed with water and dried. It was resuspended in methylene chloride A5m1) and stirred for 15 minutes before filtration. The filter-cake was washed with methylene chloride and dried to give the title compound (3.76g.

[a]21 + 25.40 (c 1.02, methanol); D 5.59 f\s, OCHCO), 6.6 to 6.9 (m, thiazole H, OCH, and catechol protons', 7.0 to 7.5 (m, NH2 and phenyl protons,' and 9.06 and 9.13 2s, OH).

Intermediate 5 (Z,S)-2-(2-Formamidothiazol-4yl)-2-[(3, 4dihydroxyphenZl)(diphenylmethoxycarbonyl)methoxyiminolacetic acid 2-f,2-Formanidothiazol-4-yl)qlyoXylic acid (6.96a) was added to a stirred solution of [(3,4-dihydroxyphenyl)(diphenylmethoxy- at cart)onyllmethoxyamine (12.73g) in N,N-dimethylformamide f10Omli ambient temperature. After 1.5 hours more N,N-dimethylformamide (40m1) was added, then at 2.5 hours the resulting solution was poured into +. f -7nn i ') wa er. m.. The products were extracted into ethyl acetate (3 x 250m1). The combined extracts were washed with water (2 x 250m1), dried over magnesiLiTi sulphate, then evaporated to a solid. This was treated with ethyl acetate (20m1) then with dichloromethane (200m1), giving a suspension. After refrigeration, the solid was collected by filtration, washed with dichloromethane, and dried to give the title compound (11..38g)m.p. 125-1270, la]D+22.20 (c 0.99, methanol).

Example 1 Diphenylmethyl (6R,7R,2'Z,S)-7-[2-(2-aminothiazol-4-yl)-2-[(3, 4dihydroxyphenyl)(diphenylmethoxycarbonyl)methoxyiminolacetamidolceph3-em4-carboxylate The tosylate salt of diphenylmethyl (6R,7R)-7-aminoceph-3-em4-carnoxylate (1.24Q) was converted into the free amine by partitioning between methylene chloride and aqueous sodium bicarbonate solution. The organic layer was washed with water and dried with magnesium sulphate. Evaporation gave a foam which was mixed with Intermediate 4 (1.0g) in THF (25ml) with stirring and N,N'-dicyClohexyicariDociiimide (830mg) and hydroxybenzotriazole hydrate (290mg) were added. After stirring at 210 for 16 hours, the mixture was filtered and the filter-cake was leached with ethyl acetate. The combined organic solutions were evaporate(I to a foam which was redissolved in ethyl acetate and filtered through a column of SorbSil U30 (100g) in ethyl acetate. Evaporation of the appropriate eluate gave the crude prociuct which was redissolved in Chloroform and loaded onto a column of SorbSil U30 (100g) set up in chloroform. The column was eluted with chloroform and then 106, 2% and 3% of methanol in chloroform. Evaporation of the appropriate eluate gave the title compound (800mg) as a foam; [a] 21 +36.250 (c 1. 17, DMSO); D - 1 a, 1 a/ 101 0 Xinfl (EtOH) 230.8 E 1 303), 290 (E "' 117) and 300.4nm (E 1 84).

em 1CM cm 26 Example 2 (6R,7R,2'Z,S)-7-[2-(2Aminothlazol-4-l)-2-E(carDOX)(3,4(jihdroxyphenyl)methoxyiminolacetamidoleeph-3-em-4-carboxylic acid, trifluoroacetic acid salt The compound of Example 1 (740mg'I was stirred with anisole 1.5ml,' and trifluoroacetic acid (7.5m1) was added. After one minute, diisopropylether (50m1) was added. The precipitate was collected by filtration, washed with diisopropyl ether and dried in vacuo to give the title compound (450mg); [a]21+102.80 ( 0.881DMS0); D C kmax (pH6 buffer) 236.8nm (E 335), Xinfl 250.0 (E 1 m 257), 277.4 1WI lem c E and 0 173, 296.Onm (E 139i em 1 0, 1 em Example 3 DiphenyImethyl (6R,7R,2'Z,S)-7E2-(2-formamidothiazol-4-l)-2-[(3, 4dihydroxyphenyl)(diphenylmethoxycarbonZl)methoximino]acetamido]ceph3-em-4-carooxylate Intermediate 5 (1.2q,' was suspended in methylene Chloride (20m1) with stirring under nitrogen and N,N-dimethylacetamide (4mE, was added. The solution was cooled to -250 and phosphorus oxychloride (0.26M1) was added. After stirring for one hour at -250 to -200, a solution of dipnenyImeth51 (6R,7R)-7-aminocepn-3-em-4-cariDoxylate (derived from its tosylate salt (1.35g,' by the action of sodium bicarbonate solution, in methyl chloride f20m1/ containing N,N-dimethylaniline f added. The reaction solution was now at 2ml) was -100 and it was then surrounded by ice-water and stirred thus for 1.75 hours. The reaction mixture was then washed successively with sodium bicarbonate solution, dilute hydrochloric acid and water three times, each time back extracting the aqueous layers with methylene chloride. The Combined organic layers were dried with magnesium sulphate and concentrated.

The crude product in methylene chloride was loaded onto a column of Sonsil U30 50g,' set up in 40% ethyl acetate in petroleum ether (BP to 600) containing 2',C') acetic acid. Evaporation of the appropriate eluate gave the title compound (1.56g); [a] 21 + 36.20 (c 1.05, DMS0); D - 101 D ?unax (EtOH) 269.2nm (E l 184) 101 cm 1 01 0 10 (E em 179), ano 266.8nm (E l cm 183) Xinfl 232.0 285), 260.4 Example 4 Diphenylmethyl (6R,7R,2'Z,S)-7-[2-(2-aminothiazol-4-yl)-2-[(3, 4dihydroxyphenyl)(diphenylmethoxycarbonyi)methoxyiminolacetamidolceph3-em4-carboxylate The compound of Example 3 (1.5g) was stirred with methanol 115ml) at 210 and 60' 0 perchloric acid (lml)was added. After 2.5 hours, the solution was partitioned between water and ethyl acetate and sodium bicarbonate solution in excess was cautiously added. The aoueous layer was extracted with more ethyl acetate and the combined organic layers were washed with brine twice, dried with magnesium sulhate and evaporated to give the title compound (1.34g); 1 [a]D + 36.50 (c 0.96, DMSO); V max Nujol) 3600 to 3100 (broad), 1785,1730 and 1680 cm-1.

Example 5 (6R,7R,2'Z,S)-7-[2-(2-Aminothiazoi-4-yi)-2-[(carboXy)(3, 4dihydroxyphenyi)methoxyiminolacetamidolceph-3-em-4-cart)oxylic acid, Sodium sait The compouncl of Example 2 (11g) was dissolved in ethanol (110ml) with stirring at 210 and saturated sodium acetate solution (4.8mi) was addea. After ten minutes, the mixture was filtered and the filter-cake was washed well with ethanol four times, ether four times and dried in vacuo to give the title compound (5.45g). A further crop (2.73g) was obtained by adding more saturated sodium acetate solution I 2ml) to the mother 1 1 quors; [a] 21 + 185.00 (c 0.78 DMSO); D - 7 lot Xmax (pH6 buffer) 234.4 fE 'o 386); Xinfl 250.4 (E 1910, 276), 276.8 lcm 1 cm - 28 1 01 ID 1 (E "' 184) and 294.4nm (E1"' m 148).

em c Example 6 (6R,7R,2'Z,S)-7-[2-(2-Aminothiazol4-l)-2-1(carbox) (3,4clihydroxyphenyl)methoxyiminolacetamidolceph-3-em-4-carboxylic acid The compound of Example 5 (1.0g) was mixed with water (4m1) and sodium acetate (4lmn) was added when a solution formed. This solution was filtered and scratching initiated crystallisation. The mixture was stored at 210 for 14.5 hours and then the crystals were collected by filtration, washed with water and dried in vacuo at 210 to give the title compound (250mQ). Addition of 2N hydrochloric acid (0.9m11. aave further crystalline product (360mq. 21 [a]D + 136.270 (c 0.54y DMS0); 1 01 1 01 1 DI 0 0 10 1 1 ' and ?max 234.4nm 'E 408,, knfl 249.6 (E 295/ 277.8 (E 192/ 101 1cm em em 295.Onm (El"' 156). em Example 7 (6R,7R,2'Z,S,'-7-[2-'2-Aminothiazol-4-l)-2-[(carbox)(3, 4dlhydroxypnenyl)methoxyimino]acetamido]ceph-3-em-4-carboxyl hydrochloric acid salt.

The compound of Example 4 '27.4g. was dissolved in formic acid 110ml) with stirring at 200 and concentrated hydrochloric acid (8.2ml,', 3 eQuivalents was added. The mixture was stirred for a further fifteen minutes and then added dropwise over six minutes to diisopropyl ether (1. 1 litres) with stirring at 200. The precipitate was collected by filtration, washed with diisopropyl ether (500m1) and dried in vacuo to qive the title compound (18.02ai v max (Nujol) 3600-2800 (broad) and 1780 cm-l; 5 3.3-3.7 (m, H-2), 5.05(d, H-6), 5.4(s, CHON,, 5.8f.m, H-7), 6. 46(m, H-3) and 9.6(d, NHCO).

Example 8 (6R,7R,2'Z,S)-7-[2-(2-Aminothiazol-4-yl)-2-[(carboxy)(3, 4dihydroxyphenyl)methoxyimino_]acetamido]ceph-3-em-4-carboxylic acid.

The compound of Example 7 (2.65q) was added, with stirring, to distilled water (10.6ml) at 200 and the mixture was stirred for thirty minutes, during which time crystallisation occurred. The stirred suspension was chilled in ice/water for fifteen minutes and then the crystals were collected by filtration, washed with chilled distilled water (10 ml) dried in an air oven at 300C to give the title compound (2.09 g); Water content 12% (Karl Fischer); IR Spectrum (Nujoi) V max 3700-2100 (broad), 1760, 1720, 1660, 1555, 1520, 1350, 1300, 12909 1240 1215, 1170, 1155, 1120, 1030, 1000, 920, 860 and 755cm-1; X-ray Diffraction Pattern (given as d spacings in Angstrtrm units and percentage intensities I). 12. 5 (21); 9.97 (37); 9.51 (22); 6.79 (11); 6.33 (35); 5.29 (10); 4.76 (30); 4.63 (100); 4.39 (54); 4.32 (5); 4.18 (15); 4.09 (31); 3.91 (24); 3.78 (69); 3.69 (17); 3.61 (9); 3.52 (12); 3.48 (21); 3.42 (6); 3.33 (37); 3. 15 (36); 3.07 (22); 3.02 (4); 2.96 (36); 2.85 (9); 2.78 (3); 2.75 (3); 2. 65 (11); 2.59 (49); 2.50 (6); 2.44 (9); 2.38 (6); 2.31 (3); 2.27 (4); 2. 20 (5); 2.16 (9); 2.10 (10); 2.05 (4); 2.01 (9).

Example 9 tert-Butyl (6R,7R,2'Z,S)-7-[2-(2-formamidothiazol-4-Z1)-2-[(3, 4dihydroxyphenyl)(diphenylmethoxycarbonyl)methoxyimino]acetamidoiceph3-em4-carboxylate.

Intermediate 5 (1.53 g) was dissolved, with stirring, in methylene chloride (15 ml) and N,N-dimethylacetamide (2.9 ml) and the solution was cooled to -350 and phosphorus oxychloride (0.41 ml) added The mixture was stirred at -250 to -200 for one hour, and then a solution of tert-butyl (6R,7R)-7-aminoceph-3-em-4-carboxylate [derived from its tosylate salt (1. 0 g) by the action of aqueous sodium bicarbonate solution as described in Example 1 for the diphenyImetnyl ester] in methylene chloride (15 ml) containing N,N-dimethylaniline (2.9 ml) was added. The reaction mixture was kept at ca. 00 for 16 hours, then washed successively with water, dilute hydrochloric acid (twice) and water; each time the aqueous layer was back-extracted with - 30 methylene chloride. The combined organic layers were concentrated to a foam, which was redissolved in methylene chloride (15 ml) and passed clown a column of "SorosiP' U30 silica (5 g) eluting with methylene chloride (30 ml). The eluate was concentrated to low volume and treated witn dlisopropyl ether (15 ml) to precipitate the title compound as a white solid (1.2 g); 1 6 'CDC'3) 1.57 (s, (CH33), 5.74 (s, OCHCO), 6.15 (m, H-7), 6.49 (C1, H-3), 8.4-8.7 (m, NHCO and -OH).

Example 10 tertButyl (6R,7R_,2'Z,5,-7-[2-(2-aminothiazol4-_l)-2-[(3, 4dihvdroxyphenyl)(diphenylmethoxycarbon1)methoxyimino]acetamidolceph 3em4-carDoxviate.

6.29 g) was stirred in methanol The compound of Example 9 64 ml and 1,4-dioxan (16m2 at 200 and 60% perchloric acid (5.63m1) was added.

After 3.5 hours, the solution was added to rapidly stirred sodium oicaroonate solution (240 ml). The mixture was stirred for a further hour and then chilled. The product was collected by filtration, washed with water and dried. It was then dissolved in a mixture of etriyl acetate and methylene chloride (1: 1) and the solution loaded onto a column of "Sorbsil" U30 silica (65 g) which was eluted with further solvent. Evaporation of the appropriate fraction of eluate gave the title compound (4.0 g); 6 1.5 (s, (CH3)3), 5.06 (d, H-6), 5.61 (s, CHON), 5.8 (m, H-7), 6.41',m, H-3), 9.0(broad, -OH), 9.5 (d, NHCO,.

Example 11 (6R,7R,2'Z,S,-7-[2-(2-Aminothiazol-4-l)-2-[(carboxy(3, 4dihydroxyphenyl)methoxyimino]acetamido]ceph-3-em-4-carboxylic acid, hydrochloric acid salt. The compound of Example 10 (1.5 a) was dissolved in formic acid (6 ml) with stirring at 200, and concentrated hydrochloric acid (0.35 ml, 2.1 eauivalents was added. The mixture was stirred for 2 hours then clarified by filtration and then evaporated under reduced pressure. Ethyl acetate (6 mly' was added to the residue and the mixture was re-evaporated to give a foam, which was triturated with ethyl acetate - 31 (6 ml). The resulting suspensio-n was stirred for 30 minutes at ambient temperature. The solid was collected by filtration, washed twice with ethyl acetate, and dried in vacuo to give the title compound (1.33 g) identical with the product of Example 7.

Pharmacy Example Dry Powder for Injection Per vial (6R,7R,2'Z,S)-7-{2-[2-Aminothiazol -4-yl]-2-[(carboxy)f3,4-dihydroxy phenyl)methoxyiminolacetamido}ceph -3-em-4-carboxylic acid.

500mg Sodium carbonate (anhydrous) 99Mg Blend the two sterile components aseptically and fill into sterile vials. Purge the vial headspace with sterile nitrogen; close the vials using rubber plugs and metal overseals fapplied by crimping). The product may be constituted by dissolving in Water for Injections or other suitable sterile vehicle shortly before administration.

32

Claims (14)

CLAIMS:

1. Compounds of formula (1) NHR 3 1 r CONH-c-o 10 H 1 1.1 N --N e 2 # 0 1/ \ H OOR 1 OCHCOOR 1 # R4 R 5 H H Z W \ 0 (I) wherein R 1 and R2, which may be the same or different, each represents a hydrogen atom or a carboxyl blocking group; R 3 represents a hydrogen atom or an amino protecting group; R 4 and R 5 each represents a hydroxy or substituted hydroxy group or R 4 and R 5 together represent a cyclic protected diol group; Z is -Sor -SO- (a- or -) and the dotted line bridging the 2-, 3-, and 4positions indicates that the compound is a ceph-2-em or ceph-3-em compound; and salts and solvates (including hydrates) thereof.

2. Compounds as claimed in claim 1 of formula (I a) NH 1 2 S / % N H H S 1 1 a/ \ 4 0 --ii ON11__1-,1, N # # 0 H 6H OCHCOOH 1 a) # R4a 5a R wherein R 4a is a hydroxy or acetoxy group; R 5a is a hydroxy or acetoxy group; and the non-toxic salts, solvates (including hydrates) and metabolically labile esters thereof.

3. Compounds of formula (Ia) as claimed in claim 2 in which the oxime etherifying group has the S-configuration.

4. (6R, 7R, 2'Z, S)-7-[2-(2-Aminothiazol-4-yl) 2-[(carboxy) (3,4-dihydroxyphenyl)methoxyi.Minolacetamidolceph- 3-em-4-carboxylic acid and the non-toxic salts, solvates (including hydrates) and metabolically labile esters thereof.

5. The compound of claim 4 in crystalline hydrated form.

6. The crystalline hydrated compound of claim 5 characterised by an infrared spectrum containing absorption bands at 3700-2100 (broad), 1760, 1720, 1660, 1555, 1520, 1350, 1300, 1290, 1240, 1215, 1170, 1155, 1120, 1030, 1000, 920, 860 and 755cm-1

7. The crystalline hydrated compound of claim 5 characterised by an X-ray diffraction pattern 0 (expressed as d spacings in Angstr6m units and percentage intensities) as follows:

34 12.5 (21); 9.97 (37); 9.51 (35); 5.29 (10); 4.76 (30) 4.32 (5); 4.18 (15); 4.09 3.69 (17); 3.61 (9) 3.33 (37); 3.15 2.85 (9); 2.50 (6) (4) 2. 20 (9) (69); 3.42 (6) (4); 2.96 (36) (11); 2.59 (49) 2.31 (3); 2.27 2.05 (4); 2.01 (22); 6.79 4.63 (100); (31); 3.91 (24); 3.78 3.52 (12); 3.48 (21); (36); 3.07 (22); 3.02 2.78 (3); 2.75 (3); 2.65 2.44 (9); 2.38 (6); (5); 2.16 (9); 2.10 (10); (11); 6.33 4. 39 (54);

8. A process for the preparation of compounds of formula (I) as defined in claim 1 or salts or solvates thereof which comprises acylating a compound of formula (II) H H Z E/ \ H2N N "40 0 H COOR 1 (wherein R, Z and the dotted line are as defined in claim 1) or a salt or a 7-N-silyl derivative thereof, with a compound of formula (III) NHR 3 N 1 0-0 r.COOH 1 N OHCOOR2 a 0 0 11 1 0 0 \ R 4 (I I) (III) (wherein R 2, R 3, R 4 and R are as defined in claim 1) or a salt thereof, or with an acylating agent corresponding thereto; 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 &2_isomer into a desired A3-isomer, ii) reduction of a compound wherein Z is -So to form a compound wherein z is -S-, iii) conversion of a carboxyl group into a non toxic metabolically labile ester function, formation of a non-toxic salt or solvate removal of any carboxyl blocking and/or N protecting groups, and removal of any hydroxy blocking groups.

iv) v) vi)

9. A process for the preparation of the crystalline hydrate of claim 5 which comprises forming an aqueous solution of (6R, 7R, 2% S)-7-[2-(2- aminothiazol4-yl)-2-[(carboxy) (3,4dihydroxyphenyl)methoxyiminolacetamido]-ceph-3-em-4-carboxylic acid or an acid addition or base salt thereof or a solvate of said salt and crystallising the said hydrate therefrom.

10. A process for the preparation of the crystalline hydrate of claim 5 which comprises forming an aqueous solution of an acid addition or base salt of (6R, 7R, 21Z, S)-7-[2-(2-aminothiazol-4-yl)-2-[(carboxy) (3,4-dihydroxyphenyl)methoxyiminol-acetamidol-ceph-3em-4-carboxylic acid or a solvate thereof and adjusting the pH of said solution to between 1.0 and 4.0.

11. A pharmaceutical composition comprising as active ingredient a compound of formula (Ia) as defined in claim 2.

- 36

12. A pharmaceutical composition as claimed in claim 11 wherein the active ingredient is a compound as defined in claim 4.

13. A pharmaceutical composition as claimed in claim 12 wherein the active ingredient is the crystalline hydrated compound of claim 5.

14. Compounds of formula (I) as claimed in claim 1 substantially as herein described.

z