Transition-metal-free S-N bond formation: synthesis of 5-amino-1,2,4-thiadiazoles from isothiocyanates and amidines

A novel and green method for the synthesis of 5-amino-1,2,4-thiadiazoles has been developed by the reaction of isothiocyanates with amidines. This protocol which is free of metal, catalyst and iodine involves O 2 oxidative S-N bond formation for the synthesis of various 5-amino-1,2,4-thiadiazole derivatives with excellent to good yields. High regioselectivity, mild reaction conditions, broad substrate scope and good functional group tolerance are the highlights of the report. A novel and green method for the synthesis of 5-amino-1,2,4-thiadiazoles has been developed by the reaction of isothiocyanates with amidines.