Synthesis and in vitro antimicrobial activity of 3-heteroarylsulphonylmethyl cephems: a new class of cephalosporins

Summary A series of 3-heteroarylsulphonylmethyl and 3-heteroarylsulphenylmethyl cephems were prepared and tested for antimicrobial activities. In contrast to the adverse effect of oxidized ring sulphur of penams and cephems on antimicrobial activities, the oxidized side-chain sulphur of 3-mercaptoheteroaryl cephems retained Gram-negative and slightly decreased Gram-positive activity. The chemical nature of the moieties substituted at C-7 and C-3 positions also influenced the antibacterial activity and spectrum. Compounds with thienyl substitution at C-7 and sulphonylmethylthiazoles or sulphonylmethylthiadiazoles at C-3 exhibited good differentials in antibacterial activity versus their unoxidized counterparts.