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.
通过氧化环合反应,以2,3-二
氯-5,6-二
氰基苯醌直接或先经乙酰化3-
硫羰基腙制得了3-(5-取代-1,3,4-
噻二唑-2-基)头孢-3-烯衍
生物。这些3-
硫羰基腙是从3-醛基头孢-3-烯和
硫羰基酰
肼反应得到的。7-
噻吩基乙酰胺基-3-(5-取代-1,3,4-
噻二唑-2-基)头孢-3-烯衍
生物(4)对革兰氏阳性菌的抗菌活性与
头孢噻吩(CET)相似,而对革兰氏阴性菌的活性则优于CET。还讨论了与其他
硫羰基腙的类似氧化环合反应。