IE48286B1 - 3-phosphonocarbamoyl-oxymethyl cephalosporins and the production of 3-carbamoyloxymethyl cephalosporins - Google Patents

Abstract

Prodn. of 3-carbamoyloxymethyl-cephalosporins (I) comprises reacting 3-hydroxymethylcephalosporins (II) with a dihalophosphinyl isocyanate (II), then converting the reaction prod., pref. by hydrolysis, to (I). Cpds. of formula (N) and their salts are new (where is R1 protected amino R2 is H or blocking gp. R3 is H, lower alkyl, alkylthio or alkoxy. Z is S or S right arrow O (alpha or beta). The dotted line indicates a ceph-3-em or ceph-2-em ring). Esp. Z is S,R2, is H and the ring is ceph-3-em. (I) are known antibiotics. (III) are easy to prepare and can be used without purificn. (IV) are intermediates during reaction of (II) and (III) and some also have activity against Gram negative and positive bacteria. They are very soluble in water and are esp. useful for treating humans and animals requiring amts of antibiotics in soln.

Description

This invention is concerned with the preparation of cephalosporin compounds substituted at the 3-position by a carbamoyloxymethyl group, and with novel cephalo5 sporin compounds.

The cephalosporin compounds in this specification are systematically named with reference to cepham after J. Amer, Chem. Soc., 1962, 84, 3400; the term cephem refers to the basic cepham structure with one double bond.

Many cephalosporin compounds possessing a degree of antibacterial activity are known in the art. These 3 compounds possess Δ unsaturation and are ordinarily substituted at the 3-position by a methyl or substituted methyl group, at the 4-position by a carboxy group, and at the 7p-position by an acylamino group. In some instances the compounds may additionally be substituted at other positions, for example at the 2-position (e.g. by one or two methyl groups or a methylene group) and/or at the 7a-position (e.g. by a lower alkyl, .....- alkoxy or alkylthio group).

One class of cephalosporin antibiotics which has attracted considerable interest comprises compounds substituted at the 3-position by a carbamoyloxymethyl group, i.e. the group -Οί^.Ο.ΟΟ,ΝΕ^; a number of antibiotics of this type, possessing a variety of 7pacylamino groups, have been proposed.

These 3-carbamoyloxymethyl cephalosporin compounds may usefully be prepared by reacting a 3-hydroxymethyl cephalosporin compound with a substituted isocyanate, i.e. a compound of formula R. NCO (I) where R is a labile protecting group, e.g. a tri chloroacetyl, 2,2,2-trichloroethoxycarbonyl or chlorosulphonyl group. This reaction leads to formation of an Nmonosubstituted 3-carbamoyloxymethyl cephalosporin wherein the 3-position substituent has the formula -ch2.o.co.nhr where R is as defined above; the labile group R may be cleaved from this product by, for example, hydrolytic, reductive or acid-induced cleavage as appropriate, to yield the desired 3-carbamoyloxymethyl cephalosporin.

A disadvantage of previously proposed processes of the above type is that the isocyanates of formula (I) which have hitherto been suggested as appropriate carbamoylating agents tend to be somewhat difficult or inconvenient to prepare, for example involving hazardous and/or expensive reagents. Moreover these reagents and the resulting isocyanates may be difficult or impossible to transport. Thus, for example, the preparationsof carbamoylating agents such as chlorosulphonyl isocyanate and trichloroacetyl isocyanate typically involve reaction of sulphur trioxide with cyanogen chloride and trichloroacetamide with oxalyl chloride respectively.

We have now discovered that 3-carbamoyloxymethyl cephalosporins may be prepared in high yield by reaction of 3-hydroxymethyl cephalosporins with dihalophosphinyl isocyanates, i.e. compounds of formula X2.PO.NCO, where each X represents a halogen atom, such as chlorine.

Such isocyanates may be prepared in relatively simple and economic .manner, if desired without isolation.

The novel N-monosubstituted 3-carbamoyloxymethyl cephalosporin intermediates initially formed in this reaction may readily be converted to the desired Nunsubstituted analogue.

Thus according to one aspect of the present invention there is provided a process for the preparation of a 3-carbamoyloxymethyl cephalosporin compound which comprises reacting a 3-hydroxymethyl cephalosporin compound with a dihalophosphinyl isocyanate and converting the resulting cephalosporin reaction product to a 3-carbamoyloxymethyl cephalosporin. 3-Hydroxymethyl cephalosporin compounds which may be used as starting materials include compounds of the formula •ch2oh (11) [wherein R^ represents a protected amino group (e.g. an acylamino group, conveniently one which contains 1-40 e.g. 1-20, carbon atoms, or a precursor therefor); R represents hydrogen or a carboxyl blocking group (e.g. the ester-forming residue of an alcohol, phenol, silanol or stannonol, the residue preferably being one 3 which may readily be split off at a later stage); R represents hydrogen or a lower (e.g. C^_^) alkyl, alkylthio or alkoxy group e.g. a methoxy group; Z is or >0 (°> or 3~);and the dotted line bridging the 2-, 3- and 4-positions of the molecule indicates that the compounds may be ceph-2-em or ceph-3-em compounds] and, where appropriate, salts (e.g. alkali metal such as sodium or potassium, alkaline earth metal such as calcium, ammonium and organic amine salts)thereof.

The 3-carbamoyloxymethyl cephalosporin final products may be represented by the formula r; ,1 '5 (III) 3 (wherein R , R , R , Z and the dotted line have the above defined meanings).

While not wishing to be bound by any theoretical considerations we have found that the process according to the invention generally proceeds in three stages.

In a first stage, the 3-hydroxyniethyl group of the cephalosporin starting material reacts with the dihalophosphinyl isocyanate to form a 3-dihalophosphorylcarbamoyloxymethyl (or dihalophosphinylcarbamoyloxymethyl) group. This group then undergoes hydrolysis - 6 α 48288 in a second stage to form a corresponding 3phosphonocarbamoyloxymethyl (or dihydroxyphosphorylcarbamoyloxymethyl) cephalosporin, which itself undergoes further hydrolysis in a third stage to give the desired product. The process is generally performed without isolation of any intermediate compounds, but we have found that the 3-phosphonocarbamoyloxymethyl product of the secorfd stage is a novel compound which may be isolated.

Thus according to a further aspect of the invention there are provided 3-phosphonocarbamoyloxymethyl cephalosporin compoundsof formula ,3 Z.

CH„0C0NH-P(0H)9 2 2 li 2 (IV) (wherein R hereinbefore defined) and salts thereof.

We have found that certain of the compounds of formula (IV) according to the invention exhibit a pharmacological activity in addition to their utility as precursors to the desired 3-carbamoyloxymethyl cephalosporin products in the process according to the invention.

Thus, preferred compounds of formula (IV) according to the invention by virtue of their pharmacological activity may be represented by the formula (V) 8286 ch9oconh-p(oh), z n z (wherein represents an acylami no group, conveniently , e.g, 1 to 25 , 3 . one which contains 1 to 40/carbon atoms, and R is as hereinbefore defined) and non-toxic derivatives thereof.

The term non-toxic as applied to the derivatives of the compounds of formula (V) of the invention means those derivatives which are physiologically acceptable in the dosages at which they are administered.

Such derivatives may include, for example, salts, physiologically acceptable esters, 1-oxides and solvates, e.g. hydrates, of the compounds of formula (V), and, where appropriate, combinations thereof.

The compounds of formula (V), of the invention, including the non-toxic derivatives thereof, are characterised in vitro by antibacterial activity against a range of gram-positive and gram-negative organisms.

The properties possessed by the compounds of formula (V) according to the invention render them useful in the treatment of a variety of diseases caused by pathogenic bacteria in human beings and 8 2 8 6 - 8 animals.

The compounds of formula (V) which form salts having good water-solubility are especially preferred since such salts are particularly valuable in cases where it is desired to administer high solution dosages of antibiotic, for example, in patients suffering from severe bacterial infection.

The above compounds of formula (V) are capable of forming base salts such as alkali metal, e.g. sodium or potassium, alkaline earth metal, e.g. calcium, and organic amine, e.g. procain^ 1-aminoadamantane, phenylethylbenzylamine, dibenzylethylene diamine, ethanolamine, diethanolamine, triethanolamine, Nmethylglucosamine and amino acid (e.g. lysine, arginine, ornithine and histidine in the d-, 1- and dl-forms) salts.

A particularly preferred compound of formula (V) containing an (α-etherified oximino)-acylamino group in the 7-position is (6R,7R)-3-phosphonocarbamoyloxy20 methyl-7-[Z-2-(fur-2-yl)-2-methoxyiminoacetamido]ceph3-em-4-carboxylic acid and non-toxic derivatives thereof. In in vitro and in vivo tests which we have carried out, it was found that this compound displayed antibacterial activity which was substantially the same as that of its 3-carbamoyloxymethyl analogue which has the approved name cefuroxime and which has been found to be a valuable broad spectrum antibiotic. When administered to mice and rats by injection, the above-mentioned compound was found to be almost completely metabolised to cefuroxime. The compound thus possesses substantially the same antibacterial activity as cefuroxime in vivo and has the advantage that it can be readily converted into salts having high water-solubility. In this respect the trisodium salt of the above-mentioned compound is particularly preferred on account of its good water-solubility.

As indicated above, the compounds of formula (V) are formed as intermediates in the process according to the invention. Thus, the*compounds of formula (V) above may be prepared by subjecting a compound of the formula (II) as hereinbefore defined to a carbamoylation reaction whereby a phosphonocarbamoyloxymethyl group is formed at the 3-position.

Compounds of formula (V) may also be prepared by condensing a compound of the formula h2m— H2OCONH-P(OH)2 (VI) 3 (wherein R , R , Z and the dotted line are as defined above) or a derivative thereof (e.g, an acid addition salt or N-silyl derivative or hydroxy-protected derivative thereof) with an acid corresponding to the acyl group of the acylamino group R or a reactive derivative thereof. In the preparation of compounds of formula (V) by either of the above two methods, any of the following reactions in any appropriate sequence may, if necessary and/or desired, be carried out!48286 - 10 (i) conversion of a precursor for the desired acylamino group into that said group, e.g. by removal of a protecting group, (ii) conversion of a Δ isomer into the desired 5 Δ isomer, (iii) removal of any carboxyl blocking group or any hydroxyl-protecting groups, and (iv) reduction of a cephalosporin sulphoxide product to yield the corresponding sulphide; and finally recovering the desired compound of formula (V), if necessary after separation of any isomers and if desired, after conversion of the compound to a nontoxic derivative thereof.

Salts, particularly non-toxic salts, of the comp15 ounds of formula (III), (IV) or (V) may be formed in any convenient way, for example according to methods well known in the art. Salt formation may take place without prior isolation of the corresponding acid, oy reaction with a suitable reagent e.g. an alkali metal bicarbonate or 2-ethylhexanoate.

The dihalophosphinyl isocyanate used in the process according to the invention is conveniently dichlorophosphinyl isocyanate by virtue of its ready availability.

It is convenient to employ substantially equimolar amounts of the 3-hydroxymethyl cephalosporin and the dihalophosphinyl isocyanate; the use of a small excess (e.g. up to 0.5 moles) of dihalophosphinyl isocyanate may, however, be advantageous to allow for side reactions between this reagent and hydroxylic impurities (e.g. - 11 48286 water) in the reaction system. In view of the susceptibility of dihalophosphinyl isocyanates to reaction with water, the reaction with the 3hydroxymethyl cephalosporin is desirably conducted under anhydrous conditions; thus, for example, the reactions may be carried out under an appropriate desiccant or the reaction system may be kept dry by passage of a stream of an anhydrous inert gas such as nitrogen.

The reaction of the 3-hydroxymethyl cephalosporin compound with the dihalophosphinyl isocyanate is conveniently carried out in solution, for example, in a substantially inert organic solvent, since this facilitates control of reaction conditions such as temperature. Solvents which may be used include chlorinated hydrocarbons such as methylene chloride or 1,2-dichloroethane; ethers such as tetrahydrofuran, dioxan or diethylene glycol dimethyl ether (diglyme); esters such as ethyl acetate; ketones such as acetone and hydrocarbons such as benzene or cyclohexane. Mixtures of solvents, e.g. comprising two or more of the above-described solvents, may also be used. As indicated above, the solvent should desirably be substantially free from hydroxylic impurities to avoid unwanted side reactions involving the dihalophosphinyl isocyanate.

The temperature employed in the reaction of the 3hydroxymethyl cephalosporin and dihalophosphinyl isocyanate may vary depending on the solvent used, but may, for example, be in the range -50° to +105 °C, e.g. - 12 43286 -20° to +50°C. The reaction is exothermic, so that cooling of the reaction system may be desirable in order to maintain a steady temperature.

The 3-hydroxymethyl cephalosporin and dihalophos5 phinyl isocyanate may be brought together in any convenient manner. Preferably a solution or suspension of the 3-hydroxymethyl cephalosporin may be added to the dihalophosphinyl isocyanate or a solution thereof. The dihalophosphinyl isocyanate may conveniently be formed without isolation as described in greater detail hereinafter.

The reaction may be monitored by, for example, chromatography, e.g. to determine the degree of consumption of the 3-hydroxymethyl cephalosporin.

Conversion of the 3-dihalophosphorylcarbamoyloxymethyl cephalosporin intermediate to the intermediate of formula (IV) and subsequently, if desired, to the cephalosporin of formula (III) may be initiated by reaction with water e.g. by addition of the reaction system to water. As indicated above, the hydrolysis to a compound of formula (III) is believed to be a multistep process. The formation of a compound of formula (IV) occurs in a first stage and this is conveniently conducted at a pH of 10 or less, e.g. 2.5 to 6. However, if it is desired to isolate a compound of formula (IV), the hydrolysis is desirably effected at a pH of from 5 to 10, preferably 7 to 9. Since the hydrolysis in the first stage is accompanied by the formation of hydrohalic acid it may be desirable to add a base to act as an acid binder. - 13 This may particularly be the case if the intermediate of formula (IV) produced is insoluble at a low pH or if the cephalosporin contains any acid-susceptible groups.

In the second hydrolysis stage, that is the conversion of the intermediate of formula (IV) to the cephalosporin of formula (III), the pH should generally be kept below pH5 and preferably in the range pH 3 to 4. In order to work in this range it may be appropriate to add either acid or base to the reaction mixture. In the hydrolysis reactions, it may be desirable to buffer the aqueous system, e.g. with sodium carbonate, sodium hydrogen carbonate, sodium acetate, sodium phosphate, calcium carbonate or calcium hydroxide, or add an acid or base such as sodium hydroxide during the course of the hydrolyses, in order to maintain the pH within the desired limits.

If it is desired to isolate a compound of formula (IV), it is generally important that the pH of the hydrolysis is not allowed to fall below values of about 5. The use of aqueous sodium hydrogen carbonate in this way has proved particularly convenient when effecting hydrolysis.

The hydrolyses may, for example, be conducted at a temperature in the range -5‘ to +105°C, e.g. +15° to +60°C, and may, where necessary, be monitored by, for example, chromatography. The reaction time is significantly affected by both the temperature and pH of the system; thus, for example, in preparing compounds of formula (III) times of 3 to 5 hours are - 48286 - 14 typically required at 40°C and pH 3 to 5, times of about 1 to 2 hours are typically required at 55°C and pH 3 to 6, while times of 20 to 30 hours or more may be required at room temperature and pH 3 to 6.

If the compounds of general formula (IV) are prepared from a starting material of formula (Vi), the condensation may be carried out, for example, in an analogous manner to that disclosed in Patent Specification No. 39764.

The above compounds of formula (VI) may be prepared for example from 7-acylamino cephalosporin analogues containing a phosphonocarbamoyloxymethyl group in the 3-position, e.g. using the technique described in British Patent Specification No. 1,041,985, the said analogue being prepared from the corresponding 3-hydroxymethyl compound in an analogous manner to the preparation of compounds of formula (IV) described above.

The compounds of formula (3$, or a base salt thereof formed in situ during the above processes for example when a base is mixed with the reaction medium after the initial step of phosphorylation, may be isolated from the reaction mixture in conventional manner, e.g. by ion exchange, treatment with adsorption resins, gel filtration, dialysis or precipitation as an insoluble salt. The compounds of formula (IV) may also be isolated as the free acid by solvent extraction from aqueous solution at low pH, e.g. at a pH below 2. - 15 both of After completion of/the hydrolyses and any necessary purification steps the desired 3-carbamoyloxymethyl cephalosporin (ill) may be isolated by, for example, conventional methods, e.g. by solvent extraction where the cephalosporin compound is a carboxyl protected derivative such as an ester or by acidification and precipitation or extraction where the cephalosporin compound is a free acid or a salt.

The dihalophosphinyl isocyanate employed in the process of the invention may readily be prepared by, for example, reaction of the appropriate phosphorus pentahalide, e.g. phosphorus pentachloride, with a carbamic acid ester, for example a lower alkyl carbamate (unless otherwise stated, the qualification lower is used in this specification to designate a group containing up to 8, e.g. 1 to 6 carbon atoms). The use of methyl carbamate is of particular advantage as this is an inexpensive reagent which is commercially available. The reaction may conveniently be accomplished by mixing the reagents in the presence of a diluent, e.g. dioxan, methylene chloride or 1,2dichloroethane, and is accompanied by the formation of hydrogen halide and alkyl halide. When phosphorus pentachloride is employed as the phosphorus pentahalide this may if desired be formed in situ by interacting phosphorus trichloride and chlorine, if desired in the presence of a diluent.

Crude dihalophosphinyl isocyanates prepared by techniques such as those described above may conveniently be reacted directly, without distillation, with the 348286 - 16 hydroxymethyl cephalosporin; in such cases it may be advantageous to ensure substantially complete removal of hydrogen halide from the crude dihalophosphinyl isocyanate, since the presence of hydrogen halide during carbamoylation may promote such undesirable side reactions as lactonisation of the 3-hydroxymethyl cephalosporin.

Acylamino groups which may be present at the 7position of cephalosporin starting materials and products in the process of the invention [e.g. as the group in formulae (II) to (V)] may, for example, be selected from the wide range of side chain acylamino groups known in the β-lactam antibiotic art. It will be appreciated that where the acylamino group carries substituents such as amino, hydroxy or mercapto groups which are susceptible to reaction with dihalophosphinyl isocyanates, these substituents should be protected by substitution with an appropriate group unless such further reaction is desired in a particular instance. Thus, for example, amino groups may be protected by substitution with a mono- or divalent blocking group, suitable groups including acyl groups, for example lower alkanoyl such as acetyl, substituted lower alkanoyl, e.g. lower haloalkanoyl and phenylacetyl,and aroyl such as benzoyl or phthaloyl; lower alkoxycarbonyl groups such as ethoxycarbonyl, isobutyloxycarbonyl or £-butoxycarbonyl and substituted lower alkoxycarbonyl groups e.g. lower haloalkoxycarbonyl such as 2,2,2-trichloroethoxy30 carbonyl; aryl-lower alkoxycarbonyl groups such as - 17 30 benzyloxycarbonyl; sulphonyl groups, for example lower alkylsulphonyl such as methanesulphonyl and arylsulphonyl such as benzene sulphonyl or p-toluene sulphonyl; ylidine groups formed by reaction with an aldehyde or ketone which forms a Schiff's base, for example acetone, methylethylketone, benzaldehyde, salicylaldehyde or ethyl acetoacetate; and divalent groups such that the nitrogen atom forms part of a dihydropyridine ring (protecting groups of this last sort oeing obtained by,&r example, reaction with formaldehyde and a β-ketoester, e.g. acetoacetic ester, as described in our Belgian Patent No. 771,694).

Hydroxyl and mercapto groups may for example, be protected by substitution with carboxylic or sulphonic acyl groups in like manner to amino groups, or, where appropriate, by etherification or thioetherification (e.g. to introduce a branched lower alkyl group such as isopropyl or t-butyl or an aralkyl group such as benzyl, benzyl substituted by one or more methoxy groups, diphenylmethyl or triphenylmethyl). The protecting groups may subsequently be removed from the cephalosporin product by methods well known in the art, for example by hydrolytic, reductive or acid-induced cleavage as appropriate.

Where the acylamino group is substituted by a carboxyl group it may also be advantageous to protect this during the course of the reaction, for example by esterification to introduce an ester group as 2 herein described in connection with the group R .

Specific acyl groups which may be present in - 48286 - 18 acylamino groups R are illustrated in the following list, which is not intended to be exhaustive:(i) ^υ^η^2η^θ" w^ere RU aryL (Carbocyclic or heterocyclic), cycloalkyl, substituted aryl, substituted cycloalkyl, cycloalkadienyl, or a non-aromatic or mesionic group, and n is an integer from 1 to 4.

Examples of this group include phenylacetyl wherein the phenyl group may if desired be substituted by, for example, one or more of fluoro, nitro, protected amino, protected hydroxy (e.g. esterified hydroxy such as acetoxy), methoxy, methylthio or methyl; N,N-bis (2-chloroethyl) aminophenylpropionyl; thien-2- and -3ylacetyl; 3- and 4-isoxazolylacetyl either substituted or unsubstituted; pyridylacetyl; tetrazolylacetyl; cyclohexadienylacetyl; or a sydnoneacetyl group.

The α-carbon atom of the acyl group may be substituted by, for example, an esterified hydroxy (e.g. acyloxy such as formyloxy or lower alkanoyloxy), etherified hydroxy (e.g. methoxy), protected amino (e.g. as hereinbefore described), carboxy, esterified carboxy, triazolyl, tetrazolyl or cyano group or a halogen atom; examples of such a-substituted acyl groups include esterified 2-hydroxy-2-phenylacetyl, Nblocked 2-amino-2-phenyl-acetyl, 2-carboxy -2?-5 phenylacetyl and esterified 2-carboxy ,-2-phenylacetyl. (ii) cnH jCO- w^ere n is 0 or an integer from 1 to 7. The alkyl group may be straight or branched and, if desired may be interrupted by an oxygen or sulphur atom and/or may be substituted by, for example, - 19 48286 a cyano group, a carboxy or esterified carboxy group (e.g. an alkoxycarbonyl group), an esterified hydroxy group, a blocked amino group or a carboxycarbonyl (-CO.COOH) or esterified carboxycarbonyl group.

Examples of such groups include formyl, cyanoacetyl, butylthioacetyl, hexanoyl, heptanoyl, octanoyl, glutaroyl, esterified glutaroyl, and N-blocked (e.g.

N-ethoxycarbonyl, or N-benzoyl) and optionally esterified R-5-amino-5-carooxypentanoyl (e.g. R-5-benzamido-5diphenylmethoxycarbonylpentanoyl or R-5-diphenylmethoxycarbony1-5-i sobutoxycarbonylaminopentanoyl).

Rv (iii) RUZC-CO- where RU has the meaning defined RW under (i) and in addition may be benzyl, RV and RW (which may be the same or different) each represents hydrogen, phenyl, benzyl, phenethyl or lower alkyl and Z is an oxygen or sulphur atom. Examples of such groups include phenoxyacetyl, 2-phenoxy-2-phenylacetyl, phenoxypropior.yl, 2-phenoxybutyryl, 2-phenoxypropionyl, methylLbiophenoxyacetyl, phenylthioacetyl, chloro- and fluorophenylthioacetyl, pyrldylthioacetyl and benzylthioacetyl. (iv) Substituted glyoxylyl groups of the formula y y R .CO.CO- wnere is an aliphatic, araliphaf.ic or aromatic group, e.g. phenyl, thienyl or furyl or a fused benzene ring. Also included in this class are the α-carbonyl derivatives of the above substituted glyoxylyl groups, e.g. the α-alkoxyimino, a-aryloxyimino and .x-aeyloxyimlno derivatives, especially - 20 those possessing the syn-configuration with respect to the 7-carboxamido group. Groups of this type, of which an example is the Z-2-(fur-2-yl)-2-methoxyimino- * acetyl group, and which may be represented by the formula R3C.CO-OR4 [wherein R represents hydrogen or an organic group (especially a carbocyclic or heterocyclic aromatic group such as phenyl, naphthyl, thienyl, thiazolyl 4 e.g. aminothiazolyl, or furyl) and R represents hydrogen, an acyl group (e.g. a lower alkanoyl, alkenoyl, alkynoyl, haloalkanoyl, alkoxycarbonyl, haloalkoxycarbonyl, alkylthiocarbonyl or aralkyloxycarbonyl group or an aroyl or carbamoyl group) or an etherifying group (e.g. a lower alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl or aralkyl group or carbocyclic heterocyclic aryl group, or any of these groups substituted by a carboxy, esterified carboxy, aminocarbonyl or N-substituted aminocarbonyl group)], are described in greater detail in Belgian Patent Nos. 778 630; 783 449; 801 997; 806 450; 823 651 and 843 152.

Where R2 in formulae (II) to (IV) and (VI) represents an esterifying group this may, for example, be selected from the wide range of esterifying groups known in the cephalosporin art. A range of groups of this type, together with methods for their .introduction and subsequent removal, are described in British Patent No. 1,342,241. Representative esterifying - 21 groups thus include aryl lower alkyl groups such as £methoxybenzyl, £-nitrobenzyl and diphenylmethyl; lower alkyl groups such as t-butyl; and lower haloalkyl groups such as 2,2,2-trichloroethyl. It will of 2 course be appreciated that R may represent an ester group in a compound which is to be used in medicine in which case this group should be physiologically acceptable. When such an ester group is employed it may not be necessary or desirable to effect deprotection of the carboxyl group.

Where at the end of a given preparative sequence the sulphoxide analogue of the compound of formula (III) or (IV) is obtained, conversion to the corresponding sulphide may, for example, be effected byreduction of the corresponding acyloxysulphonium or alkyloxysulphoniuiri salt prepared in situ by a known method, such as is described in Patent Specification No.. 39764.

As also described in Patent Specification No. 39764 a ceph-2-em-4-carboxylic ester may be converted into a desired ceph-3-em compound by treatment of the former with a base.

The antibiotic compounds of formula (V) according to the invention may be formulated for administration in any convenient way, by analogy with other antibiotics and the invention therefore includes within its scope a pharmaceutical composition comprising a compound of formula (V) or a non-toxic derivative thereof adapted for use in human or veterinary medicine. Such compositions may be presented for use in - 48286 - 22 conventional manner with Lhe aid of any necessary pharmaceutical carriers or excipients.

The antibiotic compounds of formula (V) according to the invention may be formulated with particular advantage for injection and may be presented in unit dose form in ampoules, or in multi-dose containers with added preservative. The active ingredient may be in powder form for reconstitution with a suitable vehicle, e.g. sterile, pyrogen-free water, before use. Alternatively the compositions may take such forms as suspensions, solutions and emulsions in oily or aqueous vehicles, and may contain formulatory agents such as suspending, stabilising and/or dispersing agents.

For veterinary medicine the compositions may, for example, be formulated as intramammary preparations in either long acting or quick-release bases.

In general the compositions may contain from 0.1% (w/w) S (w/w) (w/w) ‘ 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 50-1500 mg of the active ingredient. The dosage as employed for adult human treatment will preferably range from 10025 4000 mg per day, for instance 1500 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 or other cephalosporins. - 23 The following Examples serve to illustrate the invention. All temperatures are in °C. The melting point given in Example 2 was determined, ended capillary tube on a Mettler Apparatus and is uncorrected. The melting points given in Examples 8, 9 and 12 were observed on a Mettler apparatus and ' are given in the form My where x is the rate of heating in °C per minute and y is the insertion temperature.

Thin layer chromatography (TLC) using Merck Kieselgel 60 plates, run in the solvent systems indicated; detection of spots was by spraying with ninhydrin in n-butanol and heating, or by exposure to iodine vapours, or by irradiation with ultra-violet light at 254 nm. Dry solvents were used and usually contained less than 0.1% (w/v) water; the starting cephalosporins were, if necessary, dried in vacuo at 4O-5O°C and usually contained less than l%/wat:er. The ultraviolet spectra were run in pH 6 phosphate buffer, unless, otherwise specified. High pressure liquid chromatography (HPLC) was performed in a 15 cm column packed with Hyperfil FAF silica; the mobile phase was (v/v) usually 20%/methanol/0.05 molar aqueous ammonium dihydrogen phosphate; the u.v. detector was set at the Xmax of the desired product and the relative proportions of components were determined by measuring the relative absorption peak areas.

The following abbreviations have been employed in the Examples :(6R,7R)-3-carbamoyloxymethyl-7-[Z-2-(fur-2-yl)-2-methoxyiminoacetamido]ceph-3-em-4-carboxylic acid is represented as cefuroxime and the corresponding sodium salt as cefuroxime * Trade Mark .. 48286 - 24 sodium; sodium hydrogen carbonate as NaHCO^; magnesium sulphate as MgSO^; phosphorus pentachloride as PCI,.; tetrahydrofuran as THF; and dimethyl sulphoxide as DMSO.

Amberlite*XAD-2 resin consists of a synthetic cross5 linked polystyrene polymer without ionic groups attached. rt is supplied in a completely hydrated state in the form of 20 to 50 mesh (that is, 0.3 to 0.5 mm diameter) beads.

* Trade Mark - 25 48286 Example 1 Cefuroxime A solution of (6R,7R)-7-[Z-2-(fur-2-yl)-2methoxyiminoacetamidq}-3-hydroxymethylceph-3-eni-4carboxylic acid (3.81 g) in dioxan (50 ml) was stirred with dichlorophosphinyl isocyanate (2.4 g) for 5 minutes.

The reaction mixture was thereafter treated (w/v) with 3%Aqueous NaHCOg solution (148 ml) and water (2 ml), the temperature being maintained at ca 40° for .25 hours and the pH being maintained.at 5.0 by the addition of concentrated hydrochloric acid when necessary.

The pH was then raised to 6 by addition of saturated NaHCOg solution and the aqueous solution was extracted with ethyl acetate (200 ml). The aqueous phase was acidified to pH2 using concentrated hydrochloric acid and extracted with ethyl acetate (2x100 ml). The extract was dried (MgSO^) and evaporated to dryness to yield the title compound (3.67 g, 86.5%) as an off-white solid, 2fi 17 [«]„ +52.3° (c 1.03, DMSO); λ 274 nm (E, 423); purity by HPLC 96%.

Example 2 Diphenylmethyl (6R.7R)-3-carbamoyloxymethyl-7-[2-(thien2-yl) acetamido1ceph-3-em-4-carboxylate A stirred solution of diphenylmethyl (6R,7R)-3hydroxymethyl - 7 - [ 2- (thien-2-yl/-acetamido ] ceph- 3 -em-4carboxylate (5,21 g) in dioxan (50 ml) was treated with dichlorophosphinyl isocyanate (2.4 g) for 5 minutes.

Addition of 3%/aqueous NaHCO^ (100ml) to the stirred solution caused crystallisation of a large amount of solid which was re-dissolved by addition of dioxan (100 ml). The pH of ^he^solution was adjusted to 3 by the addition of 3%/aqueous NaHCO^ solution (10 ml) and the solution was maintained at ca 40° for 3 hours, whereupon TLC (chlorofornuacetone = 3:1) indicated that the reaction was complete.

The reaction mixture was extracted twice with ethyl 10 acetate (200 ml and 100 ml respectively), and the combined organic extracts were washed with saturated NaHGO^ solution (50 mi), water (50 ml), brine (2x50 ml), dried (MgSO^) and evaporated in vacuo to yield a glassy yellow solid (5.99 g). Trituration with ethanol gave the title compound (5.21 g, 92.5%) as a white solid, m.p. 207.6°; [a]p +40.9° (c 1.0, DMSO).

Example 3 Cefuroxime Dichlorophosphinyl isocyanate (1.46 ml) was added to a stirred suspension of (6R,7R)-7-[Z-2-(fur-2-yl)-2me thoxyiminoace tami do]-3-hydroxymethylceph-3-em-4carboxylic acid (3.81 g) in acetonitrile (50 ml) cooled to 5°. The reaction mixture was stirred at 5° for 15 minutes and then added to a solution of NaHCO^ (5.1 g) in water (100 ml). This mixture was stirred for 10 minutes when the pH was adjusted from 7.4 to 5.0 with hydrochloric acid. The pH fell to 3.0 after a further 10 minutes so it was readjusted to 5.0 with aqueous sodium hydroxide solution. The mixture was kept at ca. 20° overnight and - 27 then heated at 45° for 2 hours when TLC (chloroform: methanol: acetic acid=9:2:l) showed that reaction was essentially complete. The precipitated white solid was removed by filtration and the filtrate was washed with ethyl acetate. The aqueous phase was acidified to pH 1.9 with dilute hydrochloric acid in the presence of ethyl acetate. The aqueous phase was re-extracted with ethyl acetate, and the combined ethyl acetate extracts (w/v) were washed with 25%/aqueous sodium chloride solution and then evaporated. The solid residue was triturated with diethyl ether to give the title compound (3.18 g, 75.0%), purity by HPLC 95.4% and by TLC 91%.

Example 4 Cefuroxime The process of Example 3 was repeated, using dichlorophosphinyl isocyanate (1.46 ml) and a solution of (6R,7R)-7-[Z-2-(fur-2-yl)-2-methoxyiminoacetamido]-3hydroxymethylceph-3-em-4-carboxylic acid (3.81 g) in acetone (50 ml) cooled to 4°, but the reaction mixture was heated at 45° for 2 hours and then kept at 20 overnight, to give the title compound (2.40 g, 56.7%); purity by HPLC 95.6% and by TLC 94.5%.

Example 5 Cefuroxime Dichlorophosphinyl isocyanate (1.46 ml,) was added to a solution of (6R,7R)-7-[Z-2-(fur-2~yl)-2« me thoxyiminoacetami do]-3-hydroxyme thylceph-3-em-4carboxylic acid (3.81 g) in THF (50 ml) at 22°, the temperature rising to 31°. The reaction mixture was stirred for 15 minutes and then added to a solution of - 28 sodium acetate (5.72 g) in water (50 ml). More sodium acetate ( 1.64g) was added over 10 minutes to give a stable pH of 4.6. This solution was stirred at 30° for 1 hour and then heated at 45° for 3.5 hours when TLC (as Example 3) showed the reaction to be complete. The solution, pH 4.6, was clarified by filtration, adjusted to pH 7.0 with aqueous NaHCO^ solution and washed twice with ethyl acetate. The aqueous phase was stirred and acidified to pH 1.9 with dilute hydrochloric acid to precipitate the title compound (2.80 g, 66.0%); purity by HPLC 95.8% and by TLC 96%.

Example 6 Cefuroxime A solution of (6R,7R)-7-[Z-2-(fur-2-yl)-2-methoxy15 iminoace tamido]-3-hydroxymethylceph-3-em-4-carboxylie acid (3.81 g) in dioxan (20 ml) was added over ca. minute to a stirred solution of dichlorophosphinyl isocyanate (1.46 ml) in 1,2-dichloroethane (30 ml) at 19°, the temperature rising to 28°. The resulting solu20 tion was stirred for 15 minutes and then added to a solution of NaHCO^ (5.1 g) in water (70 ml). This mixture was stirred at ca. 30° for 1 hour, and then heated at 40 to 45° for a total of 4.5 hours, the pH being adjusted to 5.0 with hydrochloric acid after 3 hours. The two-phase mixture was adjusted from pH 5.8 to 7.0 with aqueous NaHCO^ solution and the aqueous phase was washed with 1,2-dichloroethane (20 ml) and ethyl acetate (50 mi), and acidified to pH 1.9 with dilute hydrochloric acid in the presence of ethyl acetate. The aqueous phase was re-extracted with ethyl - 29 acetate, and the combined ethyl acetate extract washed with 25% aqueous sodium chloride solution and evaporated. The solid residue was slurried with diethyl ether to give the title compound (3.18 g, 75.0%); purity by HPLC 91.6% and by TLC 89.5%.

Example 7 Cefuroxime Sodium (6R,7R)-7-[Z-2-(Fur-2-yl)-2-methoxyiminoacetamido]3-hydroxymethylceph-3-em-4-carboxylic acid (19.07 g) was rinsed with ethyl acetate (25 ml) into a stirred solution of dichlorophosphinyl isocyanate (7.35 ml) in ethyl acetate (100 ml) precooled to -5°. This mixture was stirred at 0° for 45 minutes and the resulting solution was added to a stirred solution of NaHCO^ (27 g) in water (270 ml) at 45°. After ca. 10 minutes the pH was adjusted to 3.0 with concentrated hydrochloric acid.

The mixture was stirred at 45° for a further 4 hours, the pH being controlled in the range 2.8 to 3.2 by the addition of hydrochbric acid, Acetone (100 ml) was added and the pH was adjusted to 2.0 with hydrochloric acid. The two-phase mixture was filtered and the aqueous phase was extracted with ethyl acetate (100 ml). The combined organic phases were washed with brine (200 ml) and then stirred with charcoal (2 g) for 30 minutes. The charcoal was removed by filtration through kieselguhr and the filter bed was washed with a mixture of acetone (20 ml) and ethyl acetate (20 ml). T^ ^ombined filtrate and wash were stirred while a 10%/solution of sodium 2ethylhexanoate in acetone was added over 18 minutes to adjust the pH of the resulting suspension to 7.0, - 30 The suspension was stirred for 10 minutes and filtered to give the title compound (18.83 g, 81.1%) containing 20 3.9% water; [a]D +60° (c 0.5; pH 4.5 phosphate buffer); purity by HPLC 93.8%.

Example 8 Cefuroxime PClj (3.160 g) and ethyl carbamate (1.566 g) were mixed and became a mobile oil on standing for ca 5 minutes (with brief ice-cooling). The oil was allowed to stand for 30 minutes at 23°, during which time all the PClj dissolved. The oil was gradually heated to 80° over 3 hours, maintained at 80° for 1 hour and allowed to cool to ca 22°. The flask containing the reaction mixture was evacuated (ca 10 to 20 mm pressure) for a few minutes, dioxan (10 ml) was added, and the flask re-evacuated.

A solution of (6R,7R)-7-[Z-2-(fur-2-yl)-2methoxyiminoace tamido]-3-hydroxymethylceph-3-em-4carboxylic acid (3,8 g) in dioxan (35 ml) was added to the above isocyanate reagent in one portion and the resulting solution was stirred at ca 2^°/for 7 minutes.

The reaction mixture was poured into 3%/aqueous NaHCO^ solution (170 ml) and the pH was adjusted to 5 by the addition of more aqueous NaHCO^ solution. After heating to 40° for 2 hours and allowing Lo cool to 22° over 14 hours, the reaction mixture was washed (at pH 5.9) with ethyl acetate (2x200 ml), the aqueous layer was separated, layered with ethyl acetate (200 ml), and acidified with concentrated hydrochloric acid to pH 1.9. The organic layer was separated and the aqueous layer re-extracted with ethyl acetate (200 ml). The organic extracts were - 31 48286 combined, washed with brine (2x400 ml), dried (MgSO^) and evaporated to give a white solid which, on trituration with ether (100 ml) afforded the title compound (3,18 g, 75%) m.p. (Μθθ) 175°; [a]D +42° (c 1.02, DMSO).

The mother liquors yielded a further quantity of crude title compound (617 mg, 14%).

Example 9 Cefuroxime This reaction was carried out on the same scale as 10 that described in Example 8 except that the ethyl carbamate was dissolved in dioxan (25 ml) and the PCl^ was added under nitrogen at ca 25°. When dissolution was complete the reaction mixture was heated from 25° to ca 75° over 1,25 hours. The temperature was maintained at ca 75° for a further 45 minutes after which the solution was cooled to ca 10°, and evacuated at water-pump vacuum for 5 minutes at 5° to remove dissolved hydrogen chloride.

A solution of (6R,7R)-7-[Z-2-(fur-2-yl)-220 methoxyiminoacetamido]-3-hydroxymethyl-ceph-3-em-4carboxylic acid (3.84g) in dioxan (35ml) was added to Lhe above isocyanate solution at ca 25°. The reaction and work up was similar to that described in Example 8, except that the product was not triturated with ether, and yielded the title compound as a pale yellow solid, (3.28g, 77%) m.p. (Μ^θ)179°; [a]*2 +54.4° (c.1.0, DMSO). - 48286 - 32 Example 10 Cefuroxime Sodium A solution of methyl carbamate (5,63 g) in dichloromethane (19 ml) was added over 12 minutes to a stirred suspension of PCl^(16.35 g) in dichloromethane (19 ml). The resulting solution was warmed gradually from 3° to reflux over 1.5 hours and then maintained at reflux for a further 4.5 hours, cooled to 20° and stored overnight. The dichloromethane was removed by distillation until the temperature of the residual dichlorophosphinyl isocyanate had risen to 110°. The isocyanate was cooled to ca. ° and dissolved in THF (50 ml), and the resulting solution was cooled to -5°. A solution of (6R,7R)-7[Z-2-(fur-2-yl)-2-me thoxyiminoace tamido]-3-hydroxy15 methylceph-3-em-4-carboxylic acid (19.07 g) in THF (75 ml), precooled to below 5°, was added over 8 minutes keeping the temperature of the mixture in the range 0 to -5°. The resulting clear solution was stirred at 0 to -10° for 45 minutes and added to water (150 ml) at 24°. 25^/Aqueous sodium hydroxide solution was added over 4 minutes to adjust the pH of the mixture to 3.0.

The mixture was heated at 45° for 3 hours 20 minutes keeping the pH in the range 3.0 to 3.5 by the periodic addition of concentrated hydrochloric acid. Ethyl acetate (125 ml) was added and the reaction mixture was worked up as in Example 7, JjuJ; using ethyl acetate as extracting solvent and a 20%/solution of sodium 2-ethyl hexanoate in ethyl acetate to give the title compound (20.71 g, 89.5%) containing 2.7^/wa^er and 0.85%^e^llyl acetate; [<*]D + 61° (c 0.5; pH 4.5 phosphate); λ (^0) 273 nm - 33 48286 (E1% 387); purity by HPLC 93.4% and by TLC 93.5%. lcm Example 11 Sodium (6R,75)-3-Carbamoyloxymethyl-7-methoxy-7phenylacetamidoceph-3-em-4-carboxylate 5 A solution of dichlorophosphinylisocyanate (0.48 g) in THF (2 ml) was added to a cooled ca. 0° solution of (6R,7S)-3-hydroxymethyl-7-methoxy-7-phenylacetamidoceph3-em-4-carboxylic acid (0.757 g) in THF (5 ml).

After 7 minutes the reaction solution was poured into water (10 ml) and after 2 minutes pH4 buffer (70 ml) was added. The pH had fallen to 1.5 and solid NaHCO^ was added to give a pH of 4.

The solution was maintained at 43° for 3¾ hours and then the pH was adjusted to 6.8 by addition of NaHCO^.

The solution was washed with ethyl acetate (35 ml).

The aqueous phase was adjusted to pH 2 by addition of orthophosphoric acid and the solution was extracted with ethyl acetate (2x50 ml).

The combined organic extracts were washed with saturated brine (2x50 ml), dried (MgSO^) and evaporated in vacuo to an oil (0.800 g).

A solution of the above oil in acetone (8 ml) was treated with a solution of sodium 2-ethylhexanoate (0.316 g) in acetone.

The resulting suspension was refrigerated for 20 minutes and the product was filtered off and washed with cold acetone (15 ml) and stirred and washed with ether (15 ml). The solid was filtered off, the filter-bed was washed with ether (15 ml) and the product dried in vacuo - 34 2o to give the title compound (0.50 g), [α]θ +199.5° (c 0.985, pH7 phosphate buffer 0.2 M), 238.5 nm (Elcm155) and 265 m (Elcm186)' Example 12 Diphenylmethyl (6R.7R)-3-carbamoyloxymethyl-7-(D-5benzoylamino-5-diphenylmethoxycarbonylpentanamido)ceph3-em-4-carboxylate A cooled (3°) solution of diphenylmethyl (6R,7R)-7(D-5-benzoylamino-5-diphenylmethoxycarbonylpentanamido)10 3-hydroxymethylceph-3-em-4-carboxylate (L.64 g) in THF (10 ml) was treated with a solution of dichlorophosphinylisocyanate (0,48 g) in THF (5 ml). The solution was stirred for 5 minutes then water (50 ml) was added.

THF (30 ml) was added to give a homogeneous solution and the pH was raised from 1.5 to 3.6 using NaHCO^ and 2N-hydrochloric acid. The mixture was kept at 44° and more THF (15 ml) was added and a two-phase system resulted.

After 3 hours the phases were separated and the aqueous layer was extracted with ethyl acetate (2x50 ml), The combined organic layers were washed successively with saturated aqueous NaHCO^ (50 ml) and saturated brine (50 ml) and the combined aqueous solutions were extracted with ethyl acetate (2x50 ml). The organic phases were combined, washed with saturated brine (50 ml) and dried (MgSO^) and evaporated in vacuo to a paleyellow solid (1.59 g)j A portion (1.48 g) of this material was crystallised from ethanol (80 ml) to give the title di-ester (1,022 g) as white crystals m.p. (M, ) ° 125 185.4°, [a] +29.2 (c, 1.01, DMSO), λ (CHC1,)259 nm » ty u , max «5 25 (E^104, ε8 995). - 35 .4-8 28 6 Example 13 (6R,7R)-3-carbamoyloxymethvl-7-[Z-2-(2-triphenylmethylaminothia2ol-4-yl)-2-methoxyiminoacetaroido]ceph-3-em4-carboxylic acid A solution of (6R,7R)-3-acetoxymethyl-7-[z-2-(2triphenylmethylaminothiazol-4-yl)-2-methoxyiminoacetamido]ceph-3-em-4-carboxylic acid (0.039 g) in 0.2 molar pH 7 phosphate buffer (40 ml) was stirred with cells of Rhodospiridium toruloides (CBS 349) at 22° for 3 hours.

The mixture was filtered through kieselguhr and the pad was washed with saturated brine (20 ml). The filtrate was washed with ethyl acetate (25 ml) cooled to 7° and acidified under ethyl acetate (25 ml) to pH 2 by the addition of orthophosphoric acid.

Filtration through kieselguhr clarified the mixture and the pad was washed with ethyl acetate (10 ml). The layers were separated and the aqueous layer was re-extracted with ethyl acetate (25 ml). The combined organic layers were washed with saturated brine (2x25 ml), dried (MgSO^) and evaporated to dryness to give a solid (0.018 g). A solution of this material (0.018 g) in dry THF (2 ml) was treated with a solution of dichlorophosphinylisocyanate (0.032 g) in THF (1 ml). After 3 minutes phosphate buffer (pH 4, 12 ml) was added and the pH adjusted to 3.8 by addition of 2N sodium hydroxide solution.

After 3¾ hours at 45° the pH was adjusted to 7.5 - 36 by addition of saturated aqueous NaHCO^ and the mixture was filtered through kieselguhr and washed with ethyl acetate (25 ml).

The pH was adjusted to 2.0 by the addition of 5 orthophosphoric acid and the solution was extracted with ethyl acetate (2x25 ml). The combined organic extracts were washed with water (20 ml) and saturated brine (20 ml) and dried (MgSO^) and evaporated to give the title compound (0.05 g) which had a similar nmr spectrum (DMSO-dg) and .TLC behaviour (R^ 0.35 in chloroform: methanol:formic acid = 90:16:4; pink colouration when sprayed with ninhydrin in n-butanol and heated) as an authentic specimen.

Example 14 (6R,7R)-3-Phosphonocarbamoyloxymethyl-7-[z-2-(fur-2-yl)2-methoxyiminoacetamido]ceph-3-em-4-carboxyiic acid trisodium salt Dichlorophosphinyl isocyanate (1.76 g) was added to a solution of (6R,7R)-3-hydroxymethyl-7-[Z-2-(fur20 2-yl)-2-methoxyiminoacetamidoJceph-3-em-4-carboxylic acid (3.81 g) in dioxan (50 ml) at 23°. After 5 minutes, (w/v) 3%/aqueous NaHCO^ solution (135 ml) was added to adjust the pH to 5.0. After 20 minutes the solution was concentrated under reduced pressure, and then washed with ethyl acetate (4 x 100 ml). Freeze-drying gave a white solid (5.91 g), a portion of which (3.50 g) was dissolved in water (50 ml) and chromatographed on Amberlite XAD-2 resin [500 g, previously slurry- 37 48286 washed with methanol (2.5 1) and water (10 1)]. The column was eluted with water, and 75 fractions each of 25 to 30 ml were collected. Fractions 20 to 29 were combined and freeze-dried to give a white solid which was triturated with ether (50 ml) to give the title 23° compound (0.74 g), [α]θ + 41.5° (c 1.03 in water); λ 273nm (ε 17 050) and λ. , 238nm (ε 10 400). max inr.

Example 15 (6R,7R)-3-Phosphonocarbamoyloxymethyl-7-[z-2-(fur-2-yl)IQ 2-methoxyiminoacetamido]ceph-3-em-4-earboxylic acid Dichlorophosphinyl isocyanate (5.28 g) in dioxan (20 ml) was added to a stirred suspension of (6R,7R)3-hydroxymethyl-7-[Z-2-(fur-2-yl)-2-methoxyimino-acetamidoJceph-3-em-4-carboxylic acid (11,44 g) in dioxan (80 ml) at 16° in a water bath; after initial addition of the isocyanate the temperature rose to 24° and eventually fell to 17°. After 10 minutes the solution was filtered under nitrogen and 1 molar aqueous NaHCO^ solution (192 ml) was added to give a pH of 7.1. The solution was extracted with ethyl acetate (2x150 ml) to remove lactone impurity. Ethyl acetate (150 ml) was then added to the aqueous phase (pH 8.2) and the pH was adjusted to 0.5 by addition of concentrated hydrochloric acid. The resultant two phase suspension was separated and the aqueous suspension extracted with n-butanol (3x250 ml). Water (30 ml) was added to the butanol extract and the aqueous layer was run off.

The organic phase was evaporated in vacuo to a thick - 38 slurry. Filtration of this slurry afforded a solid which was washed with ether (3x50 ml) as! dried in vacuo for 20 hours to give the title compound solvated with ca 1 mole of n-butanol (5.54 g), [a] & +45° (c 0.93, pH 7 phosphate buffer); ^max 273 nm (E^°m 298).

The aqueous suspension was filtered to give a solid which was washed with n-butanol (30 ml) and ether (100 ml) and dried in vacuo to give the title Λ-J compound (4.37 g), E ’ max 1cm Example 16 (6R,7R)-3-Phosphonocarbamoyloxytnethyl-7-[Z-2-(fur-2-yl)2-methoxyiminoaeetamido]ceph-3-em-4-carboxylic acid trisodium salt Portions (5.04 g and 5.73 g) of the first product obtained in Example 15 were dissolved in solutions of NaHC03 (2.52 g and 2.86 g) in water (35 ml). The solutions (pH 6.7) were applied to columns containing Amberlite XAD-2 resin [1 kg. previously washed with methanol (5 litres) and water (20 litres)]. The columns were eluted with water and fractions (ca 50 ml) were collected and examined by TLC. Fractions 15 to 25 for each product were combined (pH 8.3 and 7.5) and freeze-dried to give a solid material (3.15 g and 2.80 g).

The two solids were combined, dissolved in water (50 ml) and re-chromato'qraphed on the same column (after washing through with water (2 litres)]. 4-8286 - 39 Fractions (ca 50 ml) were collected and examined by TLC.

Fractions 22 to 30 were combined and freeze-dried to give the title compound (1.02 g), [α]ρ1+41·8° (c 1.037, H_0); λ 275 nm (E^0 297). max 1cm Example 17 Diphenylmethyl (6R,7R,5lR)-3-phosphonocarbamoyloxymethyl-7-(5-isobutoxycarbonylamino-5-diphenylmethoxycarbonyl)pentanamido-ceph-3-em-4-carboxylate A solution of diphenylmethyl (6R,7R,5*R)-310 hydroxymethyl-7-(5-isobutoxycarbonylamino-5-diphenylmethoxycarbonyl)pentanamidoceph-3-em-4-carboxylate (4.03 g) in dioxan at 25° was treated with dichlorophosphinyl isocyanate (880 mg). The solution was stirred for 6 minutes at ca 25° and was then treated (w/v) with 3%/aqueous NaHCO^ solution to give an emulsion with a pH of 5.0. After 20 minutes, TLC indicated an essentially complete reaction.

The aqueous-organic solution was partially evaporated in vacuo and a white precipitate was formed which was filtered off and washed with water and ethyl acetate and was dried in vacuo to give the title compound (2.39 g) as a crude product as evidenced by nmr spectroscopy. - 40 Pharmacy Example Dry Powder for Injection Sterile (6R,7R)-3-phosphonocarbamoyloxymethyl7-[Z-2-(fur-2-yl)-2-methoxyiminoacetamido]ceph5 3-em-4-carboxylic acid trisodium salt is filled into glass vials in an amount equivalent to 500mg of the corresponding acid. The filling is effected aseptically under a blanket of sterile nitrogen.

The vials are closed using rubber discs or plugs held in position by aluminium sealing rings, thereby preventing gaseous exchange or ingress of micro-organisms. The product may be reconstituted by dissolving in water or another suitable sterile vehicle shortly before administration by injection.

Claims (5)

CLAIMS 1. 3 (wherein R represents an acylamino group and R is as defined in claim 2) and non-toxic derivatives thereof. 8. (6R,7R)-3-Phosphonocarbamoyloxymethyl-7[Ζ-2-(fur-2-yl)-2-methoxyiminoacetamido]-ceph-3em-4-carboxylic acid and non-toxic derivatives thereof. 9. The trisodium salt of (6R,7R)-3-phosphonocarbamoyloxymethyl-7-[Z-2-(fur-2-yl)-2-methoxyiminoacetamido]-ceph-3-em-4-carboxylic acid and nontoxic derivatives thereof. 10. A process for the preparation of a compound as defined in claim 7 which comprises (a) subjecting a compound of formula (II) as defined in claim 2 to a carbamoylation reaction whereby a .dihydroxyphosphonolcarbamoyloxymethyl group is formed at the

1. A process for the preparation of a 3carbamoyloxymethyl cephalosporin compound which comprises reacting a 3-hydroxymethyl cephalosporin compound with a dihalophosphinyl isocyanate and converting the resulting cephalosporin reaction product to a 3-carbamoyloxymethyl cephalosporin. 2. 3 (wherein R , R , Z and the dotted line are as defined in claim 1) or a derivative thereof, with an acid corresponding to the acyl group of the 5 acylamido group R^ desired or a reactive derivative thereof; whereafter, if necessary and/or desired, any of the following reactions in any appropriate sequence are carried out:(i) conversion of a precursor for the 10 desired acylamido group into that said group, (ii) conversion of a Δ isomer into the desired Δ isomer, (iii) removal of any carboxyl blocking group or any hydroxy-protecting group, and 15 (iv) reduction of a cephalosporin sulphoxide product to yield the corresponding sulphide; and finally recovering the desired compound of formula (V), if necessary after separation of any isomers and if desired, after conversion of the compound 20 to a non-toxic derivative thereof. 4828S 11. A process as claimed in claim 10 substantially as herein described in any one of Examples 14 to 17. 12. Pharmaceutical compositions comprising as active ingredient a compound of formula (V) as

2. A process for the preparation of a 3carbamoyloxymethyl cephalosporin of formula (III) [wherein R represents a protected amino group; 2 R represents hydrogen or a carboxyl blocking 3 group; R represents hydrogen or a lower alkyl, alkylthio or alkoxy group; Z is X S or S -^0 (a- or β-); and the dotted line bridging the 2-, 3- and 4-positions of the molecule indicates that the compounds are ceph-2-em or ceph-3-em compounds] and, where appropriate, salts thereof, which comprises reacting a 3-hydroxymethyl cephalosporin of formula (II) - 42 12 3 (wherein R , R , R , Z and the dotted line are as hereinbefore defined) with a dihalophosphinyl isocyanate and converting the resulting cephalosporin reaction product to a compound of formula 5 (III). 3. -position;ar(b)condensing a compound of formula ,. Λ8 28 6

3. A process according to claim 2 wherein the product of the reaction of the compound of formula (II) with the dihalophosphinyl isocyanate is converted to the compound of formula (III) 1θ by hydrolysis.

4. A process according to claim 3 wherein the hydrolysis is effected in a first stage at a pH of 10 or less and in a second stage at a pH below 5. 15 5. A process as claimed in claim 1 substantially as herein described in any one of Examples 1 to 13. 6. Compounds of general formula (IV) CH OCONH-P(OH)„ II >48286 - 43 12 3 (wherein R , R , R , Z and the dotted line are as defined in claim 2) and salts thereof. 7. Compounds of general formula (V) CH.OCONH-P(OH). 2 11 2

5. Defined in claim 7 or a non-toxic derivative thereof in association with a pharmaceutical carrier or excipient.