Abstract
3-(5-Substituted-1, 3, 4-thiadiazol-2-yl) ceph-3-em derivatives were prepared by oxidative ring closure with 2, 3-dichloro-5, 6-dicyanobenzoquinone directly or after acetylation of 3-thiocarbonylhydrazones, which were obtained from the reaction of 3-formylceph-3-ems and thiocarbonylhydrazines. The antibacterial activity of 7-thienylacetamido-3-(5-substituted-1, 3, 4-thiadiazol-2-yl) ceph-3-em derivatives (4) against gram-positive organisms was similar to that of cephalothin (CET), while the activity against gram-negative organisms was superior to that of CET. A similar oxidative ring closure reaction with other thiocarbonylhydrazones is also discussed.
