SYNTHESIS OF 6,7-DIHYDRO-5H-[1,3,4]THIADIAZOLO- [2,3-b][1,3]THIAZINIUM SYSTEM DERIVATIVES

摘要

It has been shown that the reaction of 5-methyl-2-prenylsulfanyl-1,3,4-thiadiazole (1) with bromine and iodine gives halocyclization products involving the nitrogen atom of the thiadiazole ring, i.e. the 6-halo-2,5,5-tri-methyl-6,7-dihydro-5H-[1,3,4]thiadiazolo[2,3-b][1,3]thiazinium halides 2a,b. Formation of significant amounts of reaction products at the sulfur atom was not noted. The 6,7-dihydro-5H-[1,3,4]thiadiazolo[2,3-b]-[1,3]thiazinium system has previously been synthesized by reaction of 2,5-disulfanyl-1,3,5-thiadiazole with 1,3-dibromopropane [1].