Abstract: Intermediates for preparing an antibacterial 1-dethia-1-oxacephalosporins which are represented by the following formula: ##STR1## wherein R is a monovalent group (minus the carbonyl) from an acyl group derived from a carboxylic or carbonic acid;Y.sup.1 is a divalent group of the following formula: ##STR2## wherein COB is carboxy or protected carboxy;X is hydrogen or a nucleophilic group; andZ is a leaving group are prepared from a compound of the following formula: ##STR3## wherein R and Y.sup.1 are as defined above by the action of an acid. The new compounds of this invention shown by the following formula: ##STR4## wherein A is amino or substituted amino;E is hydrogen or methoxy; andY is a divalent group of the following formula: ##STR5## in which COB, X, and Z are as defined above are convertible into other compounds of the same formula by applying conventional methods in .beta.-lactam chemistry.

Abstract: An intermediate represented by following formula for synthesizing 3-hydroxy-3-cephem compounds ##STR1## wherein A and B each is a hydrogen or amino substituent; R is a hydrogen or thiol substituent; Hal is a halogen; X is a hydroxy or carboxy protecting group; the broken line between A and R shows that when R and B are hydrogens, and A is a carboxylic acyl, the substituents can be combined to form an azetidinothiazoline bicyclic ring; and the enamine derivatives thereof.

Abstract: An intermediate represented by the following formula, for synthesizing --3-hydroxy-3-cephem compounds. ##STR1## wherein A and B each is a hydrogen or amino substituent; R is a hydrogen or thiol substituent; Hal is a halogen; X is a hydroxy or carboxy protecting group; the broken line between A and R shows that when R and B are hydrogens, and A is a carboxylic acyl, the substituents can be combined to form an azetidinothiazoline bicyclic ring; and the enamine derivatives thereof.

Abstract: Azetidine derivatives of the formula: ##STR1## wherein A is amino or substituted amino; COB is carboxy or protected carboxy; R.sup.1 is .dbd.C(CH.sub.3).sub.2, ##STR2## (R.sup.4 is alkyl, aryl or aralkyl); OR.sup.2 and OR.sup.3 independently or taken together with each other represent a ketal; Y is hydrogen or methoxy; Z is hydrogen or halogen, and a process for preparation thereof. Used as intermediates in the preparation of potent antimicrobials 1-oxadethiacephalosporins.

Abstract: Useful intermediates for preparing a 1-dethia-1-oxacephalosporin and represented by the following formula: ##STR1## (wherein R is a monovalent group resulting from the elimination of the carbonyl function of an acyl group derived from a carboxylic or carbonic acid;COB is carboxy or protected carboxy; andX is hydrogen or a nucleophilic group)are prepared from the corresponding penicillin 1-oxides of the following formula: ##STR2## (wherein R, COB, and X are as defined above) by heating, if required in the presence of a desulfurizing reagent, or by exchanging the X group with another one under the condition of an appropriate nucleophilic substitution.

Abstract: Useful intermediates for preparing a 1-dethia-1-oxacephalosporin and represented by the following formula: ##STR1## (wherein R is a monovalent group resulting from the elimination of the carbonyl function of an acyl group derived from a carboxylic or carbonic acid;COB is carboxy or protected carboxy; andX is hydrogen or a nucleophilic group)are prepared from the corresponding penicillin 1-oxides of the following formula: ##STR2## (wherein R, COB, and X are as defined above) by heating, if required in the presence of a desulfurizing reagent, or by exchanging the X group with another one under the condition of an appropriate nucleophilic substitution.

Abstract: Antibacterial compounds represented by the following formula including their pharmaceutically acceptable salts and esters; process for preparing them; pharmaceutical preparation comprising them; and method for combating infections by administering them: ##STR1## (wherein Hal is halogen;R.sup.1 is hydrogen or an amino-protecting group;R.sup.2 is alkyl; andR.sup.3 is hydrogen or a carboxy-protecting group.

Abstract: Dihydrotriazinylthiomethyl-oxacephem compounds represented by the formula: ##STR1## wherein A is amino or substituted amino; COB is carboxy, protected-carboxy or a carboxy salt; E is hydrogen or methoxy; M is hydrogen or hydroxy-protecting group; and R is lower alkyl are useful as antibacterial agents.

Abstract: Antibacterial 7-substituted aminoacetamido oxadethiacephalosporins of the formula: ##STR1## [wherein R is substituted amino, substituted phenyl, or 5- or 6-membered hetero ring; Ar is aryl; Y is hydrogen or methoxy; Het is 5- or 6-membered aromatic hetero ring; and Z is hydroxy or carboxy protecting group] preparable e.g. by acylation of 7.alpha.-methoxy-7.beta.-amino-3-heterocyclic thiomethyl-3-cephem-4-carboxylic acid derivatives, are highly active against gram-positive and gram-negative bacteria, especially those resistant to other cephalosporins and penicillins.

Abstract: Useful intermediates for preparing a 1-dethia-1-oxacephalosporin and represented by the following formula: ##STR1## (wherein R is a monovalent group resulting from the elimination of the carbonyl function of an acyl group derived from a carboxylic or carbonic acid;COB is carboxy or protected carboxy; andX is hydrogen or a nucleophilic group)are prepared from the corresponding penicillin 1-oxides of the following formula: ##STR2## (wherein R, COB, and X are as defined above) by heating, if required in the presence of the desulfurizing reagent, or by exchanging the X group with another one under the condition of an appropriate nucleophilic substitution.

Abstract: 1-Oxa-cephalosporin analogues of the formula: ##STR1## [wherein X is 3-thienylmalonyl, phenylmalonyl, 4-hydroxyphenylmalonyl, or 2-fluoro-4-hydroxyphenylmalonyl;Y is hydrogen or methoxy; andR is hydrogen, alkali metal, or alkaline earth metal]and the preparation thereof.

Abstract: Intermediates (I) for preparing a potent antibacterial, 1-oxadethiacephalosporin, are shown by the following formula ##STR1## (wherein R is a group of acyl-minus-carbonyl derived from a carboxylic or carbonic acid;COB is carboxy or protected carboxy;X is hydrogen or a nucleophilic group;Y is a nucleophilic group; andZ is a leaving group)and prepared from the corresponding exomethylene compound (II) by addition of a compound of formula: Y-Z (in which Y and Z are as defined above).

Abstract: Antibacterial haloarylmalonamido-1-dethia-1-oxacephalosporins of the following formula: ##STR1## wherein Ar is ##STR2## (in which Hal and Hal' each is halogen and RO is hydroxy or protected hydroxy);COA and COB each is carboxy or protected carboxy including a pharmaceutically acceptable salt group;and Het is 1-lower alkyl-5-tetrazolyl, 1,3,4-thiadiazol-2-yl or 5-lower alkyl-1,3,4-thiadiazol-2-yl,a pharmaceutical or veterinary composition comprising the said haloarylmalonamido-1-dethia-1-oxacephalosporin and pharmaceutical carrier, and a method for treating or preventing human or veterinary infectious diseases comprising administering an effective amount of the said antibacterial compound.

Abstract: Intermediates represented by the following formulas are useful for synthesizing 3-hydroxy-3-cephem compounds ##STR1## wherein A and B each is a hydrogen or amino substituent; R is a hydrogen or thiol substituent; Hal is a halogen; X is a hydroxy or carboxy protecting group; the broken line between A and R shows that when R and B are hydrogens, and A is a carboxylic acyl, the substituents can be combined to form an azetidinothiazoline bicyclic ring; and the enamine derivatives thereof.

Abstract: Potent antibacterial cephalosporin analogues of the following formula in forms of free acids, pharmaceutically acceptable salts, or esters preparable from penicillins through azetidinone derivatives by way of a new process, and utilizable as active ingredients in bactericidal compositions for pharmaceutical and veterinary use: ##STR1## (wherein Acyl is selected from phenylacetyl, D-mandeloyl, .alpha.-phenylmalonyl, D-.alpha.-(3-methanesulfonyl-2-oxoimidazolidin-l-yl)carbonamido-.alpha.-ph enylacetyl, and 2-thienylacetyl).

Abstract: A process for preparing compounds having the formula: ##STR1## WHEREIN R is phenoxymethyl or benzyl; R.sub.2 is 1-methoxyethylidene, 1-hydroxyethylidene, or 1,1-dimethoxyethylidene; andR.sub.3 is trichloroethyl, diphenylmethyl, p-nitrobenzyl, trityl, phenyl, naphthyl, or trimethylstannyl;Which comprises treating a compound of the following formula: ##STR2## where R, R.sub.2 and R.sub.3 are as defined above, WITH AgClO.sub.4, AgBF.sub.4, AgIO.sub.4, AgPF.sub.6, CF.sub.3 COOAg, CH.sub.3 SO.sub.3 Ag, CF.sub.3 SO.sub.3 Ag, CH.sub.3 COOAg, or AgNO.sub.3 in aqueous dioxane, aqueous tetrahydrofuran or mixtures thereof.

Abstract: Antibacterial cephems having the following formula: ##STR1## (WHEREIN A is amino or substituted amino; COB is carboxy or protected carboxy;R is two hydrogens, hydrogen and a monovalent substituent, or a divalent substituent; andn is zero or one)Are prepared by reducing a compound having the following formula: ##STR2## (WHEREIN A, COB, R, and n are as defined above and X is halo or sulfonyloxy)With a reducing reagent.

Abstract: An intermediate represented by following formula for synthesizing 3-hydroxy-3-cephem compounds. ##STR1## wherein A and B each is a hydrogen or amino substituent; R is a hydrogen or thiol substituent; Hal is a halogen; X is a hydroxy or carboxy protecting group; the broken line between A and R shows that when R and B are hydrogens, and A is a carboxylic acyl, the substituents can be combined to form an azetidinothiazoline bicyclic ring; and the enamine derivatives thereof.

Abstract: A compound represented by ##STR1## is treated with a base to give an antibacterial cephem compound represented by ##STR2## (wherein A is amino or substituted amino;Cob is carboxy or protected carboxy;Rs is substituted thio;Y is an electron-attracting group selected from acyloxy, halogen, cyano, nitro, and nitroso; andThe dotted line shows .DELTA..sup.2 or .DELTA..sup.3).