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-[(2-alken-1-yl)sulfanyl]-4 H -1,2,4-triazoles

A convenient procedure for the regioselective preparation of [1,3]thiazolo[3,2- b ][1,2,4]triazol-7-ium 10 and [1,2,4]triazolo[5,1- b ][1,3]thiazin-4-ium salts 9 via regioselective electrophilic cyclization of 3-[(2-alken-1-yl)sulfanyl]-4 H -1,2,4-triazoles 3 is reported. Direction of electrophilic heterocyclization strongly depends on nature of the alkenyl substitutent.