Abstract: 7.beta.- 2-(aminothiazolyl and thiadiazolyl)-2-oxyiminoacetamido!cephalosporin derivatives having a 3- N-(optionally substituted) aminopyridiniumthiomethyl! substituent have antibacterial activity and are of use in antibacterial therapy. Processes for the preparation of such cephalosporins plus intermediates for use in the preparation thereof, including N-(optionally substituted)amino-thiopyridones, are also described.

Abstract: 7 .alpha.-formamido cephalosporin derivatives having a 3[N-(optionally substituted)aminothiopyridinium thiomethyl] substituent have anti-bacterial activity and are of use in anti-bacterial therapy. Processes for the preparation thereof and intermediates for use in these processes are also disclosed.

Abstract: .beta.-Lactam antibiotics are disclosed which have the formula (IA) or pharmaceutically acceptable salts or pharmaceutically acceptable in vivo hydrolyzable esters thereof: ##STR1## wherein R.sub.1 is phenyl, 3-hydroxyphenyl, 4-hydroxyphenyl, 3-aminophenyl, 4-aminophenyl, or 3,4-dihydroxyphenyl, the hydroxy and amino groups being optionally protected, and R is C.sub.1-8 alkyl; and also the use thereof.Processes for the preparation of the compounds are disclosed together with intermediates for use therein.

Abstract: A compound of formula (I) or a salt thereof: ##STR1## wherein R.sup.1 is an amino group, an azido group, or an acylamino group as found in antibacterially active penicillins or cephalosporins;R.sup.2 is a hydrogen atom or a C.sub.1-4 alkyl group;R.sup.3 is a hydrogen atom, or a C.sub.1-4 alkyl group optionally substituted by a carboxyl, carboxylic ester, hydroxy, C.sub.1-4 alkyloxy, acyloxy or heterocyclylthio group; andR.sup.4 is hydrogen or a readily removable carboxyl protecting group.The compounds wherein R.sup.1 is an acylamino group are found in known antibacterially active penicillins and cephalosporins and wherein R.sup.4 is a hydrogen, a pharmaceutically acceptable salting ion or an in vivo hydrolyzable ester forming radical may be formulated in pharmaceutical compositions.Processes for the preparation of the compound (I) are also described.

Abstract: The present invention provides the compounds of the formula (II): ##STR1## and pharmaceutically acceptable salts and cleavable esters thereof wherein RCONH is an organic acylamino group and E is a carboxy group or pharmaceutically acceptable salt or ester thereof or is a cyano group. Their preparation is described as is their use in compositions containing them. Compounds wherein RCONH is replaced by an azido group are described as useful intermediates.