Regio- and stereoselective synthesis of [1,3]thiazolo[3,2- b ][1,2,4]triazol-7-ium salts via electrophilic heterocyclization of 3- S -propargylthio-4 Н -1,2,4-triazoles and their antimicrobial activity

A procedure for the preparation of the title salts via regioselective halocyclization of 3- S -propargylthio-4 Н -1,2,4-triazoles is reported. Stereoselectivity of electrophilic heterocyclization depends on the nature of the electrophilic reagent: bromination is better than iodobromination and iodination. The heterocyclization with tellurium tetrahalogenides leads to the formation of a mixture of geometric isomers of the salts. Their structure was confirmed by 1 H NMR, 13 C NMR, НМВС and single crystal X-ray diffraction analysis.