SYNTHESIS AND IN-VITRO ANTIMICROBIAL ACTIVITY OF 3-HETEROARYLSULPHONYLMETHYL CEPHEMS - A NEW CLASS OF CEPHALOSPORINS

A series of 3-heteroarylsulphonylmethyl and 3-heteroarylsulphenylmethy l cephems were prepared and tested for antimicrobial activities. In co ntrast to the adverse effect of oxidized ring sulphur of penams and ce phems on antimicrobial activities, the oxidized side-chain sulphur of 3-mercaptoheteroaryl cephems retained Gram-negative and slightly decre ased Gram-positive activity. The chemical nature of the moieties subst ituted at C-7 and C-3 positions also influenced the antibacterial acti vity and spectrum. Compounds with thienyl substitution at C-7 and sulp honylmethylthiazoles or sulphonylmethylthiadiazoles at C-3 exhibited g ood differentials in antibacterial activity vet-sus their unoxidized c ounterparts.