Synthesis of [1,3]thiazolo[3,2-b][1,2,4]triazol-7-ium and [1,2,4]triazolo[5,1-b][1,3]thiazin-4-ium salts via regioselective electrophilic cyclization of 3-S-alkenylthio-4Н-1,2,4-triazoles

Abstract

A convenient procedure for the regioselective preparation of [1,3]thiazolo[3,2-b][1,2,4]triazol-7-ium and [1,2,4]triazolo[5,1-b][1,3]thiazin-4-ium salts via regioselective electrophilic cyclization of 3-S-alkenylthio-4Н-1,2,4-triazoles is reported. Direction of electrophilic heterocyclization strongly depends on nature of alkenyl substitutent: halogenation tetrahalogenhalcogenation of methallylthiotriazoles lead to formation of [1,3]thiazolo[3,2-b][1,2,4]triazole system; on the contrary, the similar halocyclization of cinnamylthiotriazoles yields the [1,2,4]triazolo[5,1-b][1,3]thiazin-4-ium salts.