Abstract: Compounds of the general formula (I): ##STR1## and pharmaceutically acceptable salts thereof, in which A, B, C and D each represent --CH.dbd. or --N.dbd., with the proviso that at least one of them is --N.dbd.;X represents --NH--, --O-- or --S--;Y represents --(CH.sub.2).sub.p -- wherein p is an integer from 0 to 4, --C(CH.sub.3).sub.2 --, --CH.sub.2 CH.dbd.CH--, --CH.sub.2 CO--, --CF.sub.2 -- or --CH.sub.2 COCH.sub.2 --;R.sup.1 represents a hydrogen atom, a C.sub.1-4 alkyl group, a halogen atom or a C.sub.1-4 alkoxy group;R.sup.2 represents a hydrogen atom, a hydroxyl group, a saturated or unsaturated C.sub.1-6 alkyl group, a C.sub.1-6 alkoxy group, a carboxyl group, a saturated or unsaturated C.sub.

Abstract: Cephalosporin compounds of the formula (I): ##STR1## wherein R.sup.1 and R.sup.2 may be the same or different and are a hydrogen atom or a lower alkyl group of 1-5 carbon atoms and A is a hydrogen atom or a nucleophilic compound residue or pharmacologically acceptable salts thereof have excellent antibacterial activity against Gram positive and Gram negative microorganisms.

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: 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: Disclosed is a novel cephem compound represented by the formula: ##STR1## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4 and Y are as defined in the specification, which is a useful intermediate for synthesizing various cephalosporin antibiotics having a methoxy group at the 7.alpha.-position thereof. Also disclosed is a process for preparing the same.

Abstract: Disclosed is a novel cephem compound represented by the formula: ##STR1## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4 and n are as defined in the specification, which is a useful intermediate for synthesizing various cephalosporin antibiotics having a methoxy group at the 7.alpha.-position thereof. Also disclosed is a process for preparing the same.