Abstract: New process for the production of the pentahydrate of ceftazidime of formula ##STR1## characterized in that the ester group of the compound of formula ##STR2## or an acid addition salt thereof, is cleaved by the sole use of aqueous hydrochloric acid, and the resulting ceftazidime is either crystallized directly from the reaction mixture as the pentahydrate by adding a base, or first of all the dihydrochloride of the ceftazidime is isolated by adding acetone and/or ethanol or another anti-solvent which is miscible with water, and this is converted into the pentahydrate by known methods.

Abstract: The invention relates to the crystalline formic acid solvate of (6R, 7R)-7-[(Z)-2-(2-Aminothiazol-4-y1)-2-(2-carboxyprop-2-oxyimino)acetamido]- 3-(1-pyridiniummethyl)ceph-3-em-4-carboxylate dihydrochloride (ceftazidime dihydrochloride).The crystalline solvate is a useful intermediate in the preparation of forms of ceftazidime suitable for administration, e.g. the pentahydrate.

Abstract: Antibacterially active novel cephalosporins of the formula ##STR1## in which R.sup.1 represents alkyl, alkenyl, alkoxy, alkylthio, halogen, trifluoromethyl or trifluoromethoxy,R.sup.2 represents hydrogen or an organic radical,R.sup.3 represents hydrogen, alkyl, alkenyl, alkoxy, alkylthio, halogen, hydroxymethyl or ethers or esters thereof, or various organothiomethyl or substituted aminomethyl radicals, andR.sup.4 represents COO.sup.- or COOH, or salts thereof.

Abstract: Cephalosporin compounds represented by the general formula (I): ##STR1## wherein R.sup.1 and R.sup.5 independently represent a hydrogen atom or a protective group for an amino group; R.sup.2 represents an alkyl group or a cycloalkyl group; R.sup.3 represents a hydrogen atom, a lower alkenyl group, an alkanoyloxymethyl group, a carbamoyloxymethyl group, a heterocyclic thiomethyl group or a heterocyclic methyl group; R.sup.4 represents a hydrogen atom or an ester residue; and X represents CH or a nitrogen atom and pharmacologically acceptable addition salts thereof, intermediate compounds used in the synthesis process of these compounds, production methods of these compounds and pharmaceutical compositions containing these compounds.

Abstract: A process for preparing compounds of the formula I: ##STR1## wherein X is sulphur, oxygen, methylene or sulphinyl (R or S configuration), R.sup.3 is hydrogen or methoxy, R.sup.4 is an optionally substituted (1-4C)alky group, Y is hydrogen or a carboxyl protecting group and Q is an optionally protected amino group or an acylamino group, which comprises reacting a compound of formula (II) ##STR2## with a compound of formula (III) ##STR3## wherein R.sup.4 is as defined above and W and Z represent hydrogen atoms or a group or groups removable to yield the compound of formula (I). The compounds of the formula I are useful intermediates in the preparation of cephalosporin antibiotics.

Abstract: Novel thiadiazolylacetamide cephem derivatives of the following formula are described. ##STR1## wherein A represents a quaternary ammonio group; or a pharmaceutically acceptable salt thereof. These novel compounds are useful as antibacterial agents, because they have a broad antibacterial spectrum ranging from gram-negative bacteria to gram-positive bacteria. Processes for the preparation of these novel compounds are also described.

Abstract: Process for the preparation of 7.beta.-amino-3-substituted methyl-3-cephem-4-carboxylic acid derivatives, new intermediates comprising 7.beta.-(cyclo)alkylideneammonio-3-halomethyl-3-cephem-4-carbox ylic acid derivatives and 7.beta.-amino/ammonio-3-bromomethyl-3-cephem-4-carboxylic acid derivatives and the processes for the preparation of these intermediates.

Abstract: A 3-propenylcephem derivative of the following formula: ##STR1## wherein R.sub.1 represents a fluoro-substituted lower alkyl group or a cyano-substituted lower alkyl group, and A represents a cyclic or an acylic ammonio group, or a pharmaceutically acceptable salt thereof, exhibiting excellent anti-bacterial activities against both Gram-positive bacteria and Gram-negative bacteria; Process for the preparation thereof; Anti-bacterial composition; Intermediate for the 3-propenylcephem derivative; and Process for the preparation of the intermediate.

Abstract: This invention relates to a compound of the formula: ##STR1## wherein Q is nitrogen or CH; R.sup.1 is hydrogen or a lower alkyl group which may be substituted; and ring A is a pyridine or pyridazine ring which is substituted at the ring-constituting carbon atom by a group of the formula:--E--(CH.sub.2).sub.n --R.sup.2in which E is sulfur or NH; R.sup.2 is an amino, carbamoylamino, formylamino, acetylamino, N-formimidoylamino, N-acetimidoylamino, lower alkylamino, hydroxyl or carbamoyloxy group; and n is an integer of 2 to 4, or a pharmaceutically acceptable salt thereof. The compound (I) or a pharmaceutically acceptable sale thereof has excellent antibacterial activity and is used as antibiotics.

Abstract: A cephalosporin derivative having the formula: ##STR1## wherein R.sup.1 is a substituted amino group, X is an alkylene group, R.sup.2 is an aryl or heterocyclic group which may be substituted and R.sup.3 is a hydrogen atom, a negative charge or a residue of an ester which can form a pharmaceutically acceptable ester hydrolyzable in a living body; or a pharmaceutically acceptable salt thereof.

Abstract: New cephalosporin derivatives of a general formula (I) and non-toxic salts and non-toxic esters thereof are provided: ##STR1## (wherein R represents an acyclic or cyclic lower alkyl group having 1-6 carbon atoms, which may optionally be substituted by a halogen atom; the steric configuration as asterisked (*) includes an optical-active (R)-form or (S)-form or an optical-inactive (RS)-form; n is 0 or 1, n.sup.1 is 0 to 3, n.sup.2 is 0 to 3; and when n.sup.1 is 0, n.sup.2 is 3; when n.sup.1 is 1, n.sup.2 is 2; when n.sup.1 is 2, n.sup.2 is 1; when n.sup.1 is 3, n.sup.2 is 0).The new derivatives of the formula (I) and non-toxic salts and esters thereof have high bactericidal activity with broad antibacterial spectra, and these are useful as active ingredients in bactericides.

Abstract: A compound having the formula: ##STR1## wherein R is a vinyl, phenyl or aralkyl group which may be substituted; or a pharmaceutically acceptable salt, physiologically hydrolyzable ester or solvate thereof.

Abstract: A cephem compound of the formula: ##STR1## wherein R.sup.1 is a group of the formula: ##STR2## in which R.sup.5 is amino or protected amino, R.sup.6 is hydrogen, lower alkyl, lower alkenyl, lower alkynyl, carboxy(lower) alkyl, protected carboxy(lower) alkyl, cyclo(lower) alkyl or cyclo (lower)alkenyl, and Z is CH or N;R.sup.2 is hydrogen, phenyl, pyridyl which may have a lower alkyl group, or cyano; andR.sup.3 is carboxy or protected carboxy; and pharmaceutically acceptable salt thereof.

Abstract: There is disclosed a process for the production of certain 3-hydrocarbyl-3-cephem derivatives wherein the hydrocarbyl group is selected from 1-alkenyl and conjugated and unconjugated 1-polyalkenyl, 1-alkynl, carbocyclic and heterocyclic aryl, and carbocyclic and heterocyclic arylmethyl and, in the case of the 1-alkenyl and conjugated 1-polyalkenyl derivatives, with substantially complete stereospecificity, by coupling a 3-triflyloxy cephem with a hydrocarbyltributylstannane in the presence of bis(dibenzylideneacetonyl)-palladium, a phosphine, and a metal halide such as, for example, zinc chloride. The 3-unsaturated alkyl-3-cephem derivatives so-produced are useful as broad-spectrum antibacterial agents.

Abstract: 1-Benzyl(or substituted benzyl)-3.beta.-[4(S)-aryloxazolidin-2-one-3-yl]-4.beta.-(2-arylvinyl)azet idin-2-ones are provided via cycloaddition of a 4(S)-aryloxazolidin-2-one-3-ylacetyl halide and an imine formed with a benzylamine and a 3-arylacrolein, e.g. cinnamaldehyde. The azetidinones are useful chiral intermediates in an asymmetric synthesis of 1-carba(1-dethia)-3-hydroxy-3-cephem-4-carboxylic acids and esters and to monocyclic .beta.-lactam antibiotics.

Abstract: Processes for the preparation of stable, crystalline cephalosporin intermediates of the formula ##STR1## wherein X is HI or HCl, and Nu and Nu.sup..sym. are certain N-containing heterocyclic rings attached via a sulfur atom or a ring nitrogen atom, respectively, which are substantially free of the .DELTA..sup.2 isomer; processes for intermediates in the preparation of the above compounds; and processes for the preparation of broad-spectrum cephalosporin antibiotics.

Abstract: According to the invention there is provided a antibacterial cephalosporin derivative of the formula: ##STR1## in which X is sulphur, oxygen, methylene or sulphinyl; R3 is hydrogen or methoxy; R1 and R2 are known in the cephalosporin art and R4 is an aminomethyl group in which the amino group carries one of various positively charged nitrogen-containing species set out in the specification and optionally a further substituent selected from hydrogen, lower alkyl, benzyl or heteroarylloweralkyl groups.

Abstract: A compound of the formula; ##STR1## wherein R.sup.1 is an amino group which may be protected, R.sup.3 is a hydrogen atom or an optionally substituted hydrocarbon residue; Z is S, S.fwdarw.O, O or CH.sub.2, R.sup.4 is a hydrogen atom, methoxy group or formamido group, R.sup.13 is a hydrogen atom, methyl group, hydroxyl group or halogen atom and A.sym. is an optionally substituted imidazolium-1-yl group forming a condensed ring at the 2,3- or 3,4-position or a pharmaceutically acceptable salt or ester thereof is novel and has excellent antibacterial activity.

Abstract: A compound of the formula: ##STR1## wherein R.sup.1 is lower alkyl, lower alkanoyl, aryl, ar(lower)alkyl or a heterocyclic group, each of which may have suitable substituent(s),R.sup.2 is carboxy or protected carboxy,R.sup.3 is hydrogen, halogen, hydroxy, lower alkoxy, acyloxy, lower alkylthio, lower alkenyl, lower alkenylthio, lower alkynyl, heterocyclicthio or a heterocyclic group, in which lower alkylthio, lower alkenyl, lower alkenylthio, heterocyclicthio and a heterocyclic group may have suitable substituent(s),R.sup.4 and R.sup.5 are each hydrogen, halogen or arylthio,A is lower alkylene, andn is an integer of 0 or 1,and a pharmaceutically acceptable salt thereof, processes for preparation thereof and pharmaceutical composition comprising the same.

Abstract: A cephalosporin derivative represented by the formula ##STR1## wherein R is an organic residue known on .beta.-lactam antibiotics and Q is a radical of ##STR2## dotted-line means a possible double bond, R.sub.1 is hydrogen or monovalent substituent, R.sub.2, R.sub.3 and R.sub.4 are mono-valent substituent, respectively,a salt thereof, a process for the manufacture thereof and a pharmaceutical agent comprising same.

Abstract: A cephalosporin derivative of the formula I: ##STR1## in which X is S, O, CH.sub.2 or SO, R1 is (optionally-substituted) imidazol-2-yl or one of the C-7 acyl groups known in the cephalosporin art, R2 is hydrogen or methoxy, R3 is carboxy or a biodegradable ester thereof and -R4 is of the formula XII, XIII or XIV: ##STR2## in which R32-R40 inclusive are as defined in the specification; and the salts thereof. Pharmaceutical compositions, methods of manufacture and intermediates are also described.

Abstract: Various 7-amino-3-substituted-methyl-3-cephem-4-carboxylic acids and lower alkylsily derivatives such as 7-amino-3-(2,3-cyclopenteno-1-pyridiniomethyl)-3-cephem-4 -carboxylic acid iodide and trimethylsilyl 7-trimethylsilylamino-3 -(5,6,7,8-tetrahydro-2-isoquinoliniomethyl)-3-cephem-4 -carboxylate iodide are valuable intermediates in the preparation of new and novel antibacterial agents. A new process for the preparation of these acids and the derivatives has been devised.

Abstract: A compound of the general formula: ##STR1## wherein R.sup.0 is hydrogen, a nitrogen-containing heterocyclic group, an acyl group or an amino-protective group; A is S, S.fwdarw.O, O or CH.sub.2 ; R.sup.4 is hydrogen, methoxy group or formamido group; R.sup.13 is hydrogen, methyl, hydroxyl or a halogen; and A is an optionally substituted condensed cyclic group formed by combining an imidazole or pyrazole ring with 5- or 6-membered nitrogen-containing aromatic heterocyclic ring to share a C-N bond with each other,or a salt or ester thereof.and a process for preparing the same and a pharmaceutical composition thereof are disclosed.

Abstract: Cephem compounds of the formula: ##STR1## wherein Q stands for a nitrogen atom or CH, R.sup.1 stands for a hydrogen atom or an optionally substituted lower alkyl group, R.sup.2 stands for a hydrogen atom or a lower alkyl group, A stands for a sulfur atom or NH, and n denotes an integral number ranging from 2 to 4, or salts thereof, and processes for producing them. The compounds (I) or salts thereof show not only excellent antibacterial activities against a wide range of pathogenic bacteria from gram-positive to gram-negative ones, including a variety of strains isolated clinically but also hydrophilic properties, and therefore they are excellent antibiotic substances having desirable water-solubility when used as injections.

Abstract: Novel cephalosporin derivatives and salts thereof are disclosed. These compounds exhibit excellent antimicrobial activity against a wide variety of Gram-negative and Gram-positive bacteria and also have other excellent characteristics as a medicine such as stability and low toxicity. These compounds can be administered in a form of subcutaneous, intravenous or intramuscular injections.

Abstract: The invention provides crystalline (6R, 7R)-7-[[2-(2-Amino-4-thiazolyl)-(Z)-2-(1-diphenylmethoxycarbonyl-1-methyle thoxy)imino ]acetamido]-3-(1-pyridiniummethyl)-3-cephem-4-carboxylate and a process for its production.

Abstract: A compound having the general formula ##STR1## wherein, R.sup.0 is a hydrogen atom, a nitrogen-containing heterocyclic group, an acyl group or an amino-protective group; Z is S, S.fwdarw.O,O or CH.sub.2 ; R.sup.4 is a hydrogen atom, a methoxy group, or a formamide group; R.sup.13 is a hydrogen atom, a methyl group, a hydroxyl group, or a halogen atom; A.sym. is a condensed triazolio group which may be substituted, or a pharmaceutically acceptable salt or ester thereof is novel and has an excellent antibacterial activity.

Abstract: A cephalosporin compound having the formula: ##STR1## wherein R.sub.1 is a hydrogen atom, a halogen atom, a methoxy group, a substituted or unsubstituted vinyl group, or --CH.sub.2 --A wherein A is a hydrogen atom, an azido group, an acyloxy group, a carbamoyloxy group, a subsituted or unsubstituted heterocyclic group (wherein the hetrocyclic ring is a 5- or 6-membered heterocyclic ring having from 1 to 4 oxygen, nitrogen or sulfur atoms), or a substituted or unsubstituted heterocyclic thio group (wherein the heterocyclic ring is a monocyclic or bicyclic heterocyclic ring having from 1 to 5 oxygen, nitrogen or sulfur atoms), or a pharmaceutically acceptable salt thereof.

Abstract: The compound having the formula: ##STR1## wherein R is a straight chain, branched chain or cyclic lower alkyl, a lower alkenyl or a lower alkynyl group which may be substituted by a carboxyl group, and R.sup.1 is hydrogen atom or an acetyl group; or a pharmaceutically acceptable salt, physiologically hydrolyzable ester or solvate thereof.

Abstract: Cephalosporin compounds having 2-(2-aminothiazol-4-yl)-2{(1S)-carboxyethoxyimino}acetyl group on the side chain at the 7-position thereof and 1-ethylpyridinium-4-ylthiomethyl group on the side chain at the 3-position thereof or non-toxic salts thereof are excellent antibacterial agents for mammals including human. The cephalosporin derivatives have low toxicity.

Abstract: A process for preparing cephalosporin compounds represented by the formula ##STR1## wherein R.sup.1 represents an alkyl group, alkenyl group, substituted or unsubstituted aryl group, substituted or unsubstituted arylmethyl group or substituted or unsubstituted phenoxymethyl group, R.sup.2 represents a carboxyl group or protected carboxyl group, and Y represents the residue of a nucleophilic reagent.

Abstract: There is disclosed a novel .beta.-lactam antibiotics represented by the formula: ##STR1## wherein A is a group represented by the formulae -NHCO--, --NHCONHCO--, --NHCOCH.dbd.CH-- or ##STR2## where R.sub.6 is a hydrogen atom or a lower alkyl group; R.sub.1 and R.sub.2 are independently a hydrogen atom or a protective group; R.sub.3 is a hydrogen atom or a methoxy group; X is a hydrogen atom, a hydroxyl group, a protected hydroxyl group, a halogen atom, a lower alkoxy group or a nitro group; n is an integer of 1 or 2; Y is a group represented by the formulae: ##STR3## provided that a carbon atom which is bonded by a carboxyl group being bonded to nitrogen atom; M is a hydrogen atom, a protective group or an easily hydrolyzable group in a human body; R.sub.7 is a hydrogen atom, a methyl group a lower alkoxy-methyl group or a group represented by the formula: --CH.sub.

Abstract: The invention relates to the novel compound (6R,7R)-7-(D-5-benzamido-5-carboxypentanamido)-3-(1-pyridiniummethyl)-ceph -3- em-4-carboxylate and salts thereof, which may be prepared in substantially pure form. The novel compounds are useful for the preparation of (6R,7R)-7-amino-3-(1-pyridiniummethyl)ceph-3-em-4-carboxylate or salts thereof, which are themselves useful for the preparation of 7-substituted 3-pyridiniummethyl cephalosporin antibiotics such as ceftazidime and cephaloridine.

Abstract: A novel method of producing a cephalosporin compound of the formula ##STR1## wherein R.sup.1 is a hydrogen atom or an acyl group; R is a hydrogen atom or an ester residue; the dotted line means a double bond in 2- or 3-position of the cephem ring; and R.sup.4 is a nucleophilic compound residue, or a salt thereof, directedly in one step from a compound of the formula ##STR2## wherein R.sup.1, R and the dotted line have the meanings defined above, or a salt thereof, by reacting in the presence of an organic solvent the compound [II] or a salt thereof, a nucleophilic compound or a salt thereof, and (1) a trivalent or pentavalent cyclic phosphorus compound having a partial structure of the formula ##STR3## wherein W is an oxygen atom, a sulfur atom or NR.sup.2 ; W.sup.1 is an oxygen atom, a sulfur atom or NR.sup.3 ; and R.sup.2 and R.sup.

Abstract: A new cephalosporin compound is now provided, which is useful as antibacterial agent and is represented by the general formula (I) ##STR1## wherein R.sup.1 is an amino group or a protected amino group; R.sup.2 is a hydrogen atom, a salt-forming cation or a carboxyl-protecting group; R.sup.3 is a hydrogen atom, a halogen atom, a lower alkylthio group, a lower alkoxyl group, a vinyl group or a group of the formula: --CH.sub.2 Y where Y is a hydrogen atom, a halogen atom, an acyloxy group, an unsubstituted or substituted heterocyclic thio group or an unsubstituted or substituted pyridinio group, and a pharmaceutically acceptable salt or ester thereof.

Abstract: A compound of the formula; ##STR1## wherein R.sup.0 stands for hydrogen atom, nitrogen-containing heterocyclic group, acyl group or esterified carboxyl group, Z stands for S, S.fwdarw.O, O or CH.sub.2, R.sup.4 stands for hydrogen atom, methoxy group or formamido group, R.sup.13 stands for hydrogen atom, methyl group, hydroxyl group or halogen atom and A stands for an optionally substituted imidazol-1-yl group forming a condensed ring at the 2,3- or 3,4-position or a physiologically or pharmaceutically acceptable salt or ester thereof.This compound is novel and has excellent antibacterial activity.

Abstract: A cephalosporin compound of the formula: ##STR1## wherein: R.sup.2 is a group of the formula: ##STR2## R.sup.4 is a lower alkenyl group, a lower alkyl group or a lower alkyl group substituted with a member selected from the group consisting of cyano, lower alkylthio, 2-(lower alkyl)-1,3,4-thiadiazol-5-yl, carbamoyl, thiocarbamoyl, and N-lower alkyl(thiocarbamoyl) andR.sup.5 and R.sup.6 are each a hydrogen atom or a lower alkyl group, or a pharmaceutically acceptable salt thereof, is disclosed. These compounds have antimicrobial activity.

Abstract: A cephalosporin compound of the formula: ##STR1## wherein R.sup.1 is a protected or unprotected amino group;either one of R.sup.2 and R.sup.3 is a substituted or unsubstituted lower alkylthio group; sulfamoyl group; a lower alkylsulfonyl group; sulfo group; a substituted or unsubstituted amino group; a lower alkyl group; a lower alkyl group having a substituent selected from a lower alkylthio group, amino group and an acylamino group; a halogen atom; carboxy group or a lower alkoxy group; andthe other one of R.sup.2 and R.sup.3 is hydrogen atom; carbamoyl group; a substituted or unsubstituted amino group; a lower alkyl group or a hydroxy-lower alkyl group; orR.sup.2 and R.sup.3 are combined together to form a lower alkylene group;or a salt thereof and processes for preparing the same are disclosed. The cephalosporin compound (I) is useful as an antimicrobial agent.

Abstract: This is a class of antibacterial compounds of the formula: ##STR1## wherein Y is straight or branched alkyl or alkenyl chain, cycloalkanomethyl of 3-6 carbon atoms, each group being optionally substituted by halogen, or a group ##STR2## wherein n is 0 or an integer of 1-3, A is a group --COR.sup.3 wherein R.sup.3 is hydroxy, a group ##STR3## wherein R.sup.4 and R.sup.5, which may be the same or different, are hydrogen or alkyl of 1-5 carbon atoms, a group ##STR4## or a 5- or 6-membered heterocyclic group containing nitrogen and/or sulfur, and R.sup.1 and R.sup.2, which may be the same or different, are hydrogen, alkyl of 1-5 carbon atoms, or R.sup.1 and R.sup.2 may be combined together to form cycloalkylidene of 3-5 carbon atoms, and Z is a group of the formula: ##STR5## wherein m is 0 or an integer of 3-5, R.sup.6 is hydrogen or alkyl of 1-3 carbon atoms, and R.sup.7, when m is an integer of 3-5, is alkyl of 1-5 carbon atoms, alkenyl, cyclopropyl, a group --(CH.sub.2).sub.

Abstract: A process for recovering ceftazidime from an aqueous solution containing it, said solution being at a pH in the range 2.0 to 5.5, which comprises contacting the said solution with a non-functional macroreticular resin suitable for adsorbing ceftazidime, eluting the ceftazidime and isolating it, if desired in the form of a salt or hydrate.

Abstract: Process for the production of known 2-oximinoacetamido-3-cephem-4-carboxylic derivatives comprising acylation of 7-amino-3-cephem-4-carboxylic acid derivatives with novel 2-oximinoacetic acid thio esters, as well as such thioesters and their production.

Abstract: The invention relates to antimicrobial compounds of the formula: ##STR1## wherein R.sup.1 is amino or a protected amino group,R.sup.2 is carboxy or a protected carboxy group andR.sup.3 is thiadiazolylthiomethyl or thiadiazolylthiomethyl substituted with lower alkyl, and pharmaceutically acceptable salts thereof.

Abstract: Cephem derivatives of the general formula ##STR1## in which the R.sub.2 O group is in the syn-position, a process for their manufacture and pharmaceutical formulations which are active against bacterial infections and contain these compounds.

Abstract: Cephalosporin compounds represented by the following formula (I) and pharmaceutically acceptable salts thereof have a broad bactericidal spectrum against various pathogenic bacteria including Psuedomonas aeruginosa and are useful as bactericidal remedies for pathogenic diseases of human and animals: ##STR1## wherein A represents an unsubstituted or substituted pyridylthio group of a formula (I-1); ##STR2## or an unsubstituted or substituted pyridiniumthio group of a formula (I-2): ##STR3## or an unsubstituted or substituted pyridinium group of a formula (I-3); ##STR4## or a 5- or 6-membered heterocyclicthio or bicycloheterocyclicthio group of a formula (I-4):--S--Het (I-4).

Abstract: Antibacterially effective cephalosporins of the formula ##STR1## in which R.sup.1 denotes C.sub.1 -C.sub.6 -alkyl, phenyl or halogen-substituted phenyl andA represents a nitrogen-containing, positively charged heterocyclic 5-membered to 7-membered ring which is bonded via N and can contain a total of up to 4 hetero-atoms from the group comprising N, O and S, and onto which up to two further rings can be fused, and which can optionally be substituted, with the proviso that, if the ring is a 6-membered ring, A does not represent an unsubstituted pyridine ring or a pyridine ring which is mono- or di-substituted by identical or different substituents from the group comprising C.sub.1 -C.sub.4 -alkyl, chlorine, bromine, carbamoyl or N--C.sub.1 -C.sub.4 -alkylcarbamoyl,or pharmaceutically acceptable salts thereof or esters thereof which can be split under physiological conditions.

Abstract: 7-Amino-3-(3-formamidopyridinium)methyl-3-cephem-4-carboxylate of the formula ##STR1## is produced by (a) reacting a compound of the formula ##STR2## in which R.sup.3 is phenacetyl or a thienylacetyl group, with 3-formamidopyridine to give the compound of the formula ##STR3## and (b) spliting off the R.sup.3 radical. The product can then be coupled to a suitable acid to produce a cephalosporin and the formyl radical may be split off.

Abstract: A process for the preparation of a cephalosporin of the formula ##STR1## in which R.sup.1 is an aliphatic or cycloaliphatic radical with up to 6 carbon atoms, andA is a pyridinium radical or a radical of the formula ##STR2## comprising reacting an acid of the formula ##STR3## with methanesulphonyl chloride to form an anhydride of the formula ##STR4## and reacting the anhydride with a 7-aminocephalosporanate of the formula ##STR5## The reaction proceeds smoothly and in high yield.

Abstract: 7-[2-(5-Amino-1,2,4-thiadiazol-3-yl)-2-(substituted)-iminoacetamido]-3-[3-( quaternaryammonio)-1-propen-1-yl]-3-cephem-4-carboxylates of the formula ##STR1## in which R.sup.1 and R.sup.2 are defined herein and --.sup..sym. N.tbd.Q is a quaternary ammonio group as defined herein, and salts, solvates, hydrates and esters thereof, are potent antibacterial agents. Processes for their preparation and intermediates in such processes are described.

Abstract: An antibacterial 7beta-(carboxyalkenoyl)amino-3-cephem-4-carboxylic acid represented by the following formula: ##STR1## (wherein R is aryl or a heterocyclic group; R.sup.1 is hydrogen or halogen;R.sup.2 is a single bond, alkylene, or thiaalkylene;R.sup.3 is a hydrogen atom or carboxy modifying group;R.sup.4 is hydrogen or methoxy;R.sup.5 is hydrogen or a 3-substituent of cephalosporins;R.sup.6 is a hydrogen atom or carboxy modifying group; andX is oxygen, sulfur, or sulfinyl)a pharmaceutical composition containing the same, and a method for treating a bacterial infection with the same.

Abstract: Cephalosporin compounds substituted in the 7-position by a 2-(5- or 6-membered heterocyclic)-2-oximinoacetylamino group and in the 3-position with an imidazolo, oxazolo or thiazolopyridinium-methyl group are broad spectrum antibiotics highly effective in combating bacterial infections of gram-negative and gram-positive microorganisms. The cephalosporins are best prepared by reacting a silylated 7-[2-(heterocyclic)-2-oximinoacetylamino-3-iodomethyl-3-cephem-4-carboxyli c acid with an imidazolopyridine, an oxazolopyridine or a thiazolopyridine. Pharmaceutical formulations comprising a compound of the invention and a method for treating bacterial infections comprising their use are also provided.