Abstract: A process for preparing a .beta.-lactam compound of the formula (I): ##STR1## which comprises cyclization of an azetidinone derivative of the formula: ##STR2## is provided in which R.sup.1 is hydrogen, alkyl which is optionally substituted, or amino which is optionally substituted; R.sup.2 is a carboxy-protecting group; and X is alkylene which is optionally intervened by --O-- or --S--, and/or which is optionally substituted; and R.sup.3 is aryl which is optionally substituted.

Abstract: A process for preparing a .beta.-lactam compound of the formula (I): ##STR1## which comprises cyclization, in the presence of a catalyst, of an azetidinone derivative of the formula: ##STR2## is provided in which R.sup.1 is hydrogen, alkyl which is optionally substituted, or amino which is optionally substituted; R.sup.2 is a carboxy-protecting group; and X is alkylene which is optionally intervened by --O-- or --S--, and/or which is optionally substituted; and R.sup.3 is aryl which is optionally substituted. The catalyst is preferably a transition metal salt (especially rhodium) or is an acid.

Abstract: A compound of the formula I: ##STR1## wherein Acyl is C.sub.1 -C.sub.12 acyl; Het is an optionally substituted monocyclic heteroaromatic group containing one or more hetero atoms; R.sup.1 is a single bond or C.sub.1 -C.sub.4 alkylene; R.sup.2 is a straight or branched C.sub.1 -C.sub.4 alkylene; and Y is a hydrogen atom or methoxy group, or a pharmaceutically acceptable salt or an amino-, carboxy- and/or hydroxy-protected derivative thereof, which have a potent antibiotic activity.

Abstract: A novel thioalkylthio cephalosporin antibiotic compound of formula I: ##STR1## wherein Acyl is C.sub.1 -C.sub.12 acyl; Het is optionally substituted monocyclic heteroaromatic group containing one or more hetero atoms; R.sup.1 is a single bond or C.sub.1 -C.sub.4 alkylene; R.sub.2 is a straight or branched C.sub.1 -C.sub.4 alkylene; X is a sulfur atom or sulfoxide group; and Y is a hydrogen atom or methoxy group, or a pharmaceutically acceptable salt or an amino-, carboxy- and/or hydroxy-protected derivative thereof, a formulation containing the same and a method for treating bacterial infections.

Abstract: A novel thioalkylthio cephalosporin antibiotic compound of formula I: ##STR1## wherein Acyl is C.sub.1 -C.sub.12 acyl; Het is optionally substituted monocyclic heteroaromatic group containing one or more hetero atoms; R.sup.1 is a single bond or C.sub.1 -C.sub.4 alkylene; R.sub.2 is a straight or branched C.sub.1 -C.sub.4 alkylene; X is a sulfur atom or sulioxide group; and Y is a hydrogen atom or methoxy group, or a pharmaceutically acceptable salt or an amino-, carboxy- and/or hydroxy-protected derivative thereof, a formulation containing the same and a method for treating bacterial infections.

Abstract: An oral antibacterial, 7beta-[(Z)-2-(2-aminothiazol-4-yl)-2-alkenoylamino]-3-cephem-4-carboxylic acid pharmaceutically acceptable ester represented by the following formula: ##STR1## (wherein R is amino or protected amino,R.sup.1 is straight, branched, or cyclic alkyl optionally substituted by alkoxy,R.sup.2 is hydrogen or a 3-substitutent of cephalosporins,R.sup.3 is a pharmaceutically acceptable ester group, andX is sulfur or sulfinyl).

Abstract: Antibacterial 7.beta.-(oxo-saturated heterocyclic carbonamido)-3-cephem-4-carboxylic acid derivatives of the formula: ##STR1## (wherein R is hydrogen or methoxy; R.sup.1 is hydrogen or a nucleophilic group; R.sup.2 is hydrogen, light metal, or a carboxy protecting group; X is oxygen, sulfur, sulfinyl, or sulfonyl; Y is alkylene containing one or more hetero atoms; and Z is hydrogen or a substituent).

Abstract: A compound of the formula: ##STR1## wherein u represents hydrogen, carboxamido, N-hydroxycarboxamido, carboxy, azido, an aryl, an acylamino, a protected carboxy or an N-alkoxycarboxamido, or, together with v, can represent --S-- or --CH.sub.2 S--; v represents hydrogen, halogen, cyano or an alkylthio, or, together with u, can represent --S-- or --CH.sub.2 S--, or, together with w, can represent --(CH.sub.2).sub.3 CO--; w represents hydrogen, carboamoyl, cyano, carboxy, an N-alkylcarbamoyl, an alkyl, an aryl, a protected carboxy or a heterocycle, or, together with v, can represents --(CH.sub.2).sub.