Synthesis of novel 4-substituted 1,2,3-thiadiazoles via iodine-catalyzed cyclization reactions

[Display omitted] •An efficient iodine-catalyzed the reaction of the ester-substituted N-tosylhydrazones with S8 was developed.•Various novel 4-substituted 1,2,3-thiadiazoles were synthesized.•The synthetic potential is demonstrated by gram-scale synthesis and further transformations. Iodine-catalyzed the reaction of substituted methyl ketone N-tosylhydrazones with elemental sulfur has been developed. The cyclizations of the ester-substituted N-tosylhydrazone substrates proceeded smoothly under optimal reaction conditions, and the corresponding products 4-alkyl-1, 2, 3-thiadiazoles are obtained. For the reaction of 4-arylbutan-2-one of N-tosylhydrazone substrates, (E)-4-styryl-1, 2, 3-thiadiazole derivatives were obtained with high selectivity through the control of reaction conditions. In addition, gram-scale synthesis and further transformation of the product were also investigated.