N-取代环十二酮缩氨基硫脲的氧化环合反应

以环十二酮为起始物合成的一系列N-取代环十二酮缩氨基硫脲(Ⅰ)经二氧化锰氧化环合为2-(1,11-十一亚甲基)-5-取代亚氨基-△^3-1,3,4-噻二唑啉(Ⅱ)。Ⅱ的结构得到IR，13^CNMR和元素分析的确证。反应中同时分离到一个副产物，经IR，13^CNMR,EIMS和元素分析确定其结构为2-(1,11-十一亚甲基)-5-亚氨基△^3-1,3,4-噻二唑啉(Ⅲ)。据此提出了Ⅰ经二氧化锰氧化环合为Ⅱ的两步反应机制，此机制可以合理地解释Ⅱ和Ⅲ的生成。

Oxidative cyclisation of N-substituted cyclododecanone thiosemicarbazones

N-Substituted cyclododecanone thiosemicarbazones Ⅰ, prepared from cyclododecanone, undergo oxidative cyclisation on treatment with manganese dioxide giving 2-(1,11-undecylidene) -5-substituted imino-△ ^3-1,3,4-thiadiazolines Ⅱ. The structures of Ⅱ were confirmed by IR, 13^C NMR and elemental analysis. A by-product was separated from the reaction mixture and its structure was assigned as 2-(1,11- undecylidene)-5-imino- △ ^3-1,3,4-thiadiazoline Ⅲ by IR, 13^C NMR, EIMS and elemental analysis. A two-step reaction mechanism for the oxidative cyclisation of Ⅰ on manganese dioxide was proposed to explain the formation of Ⅱ and Ⅲ.