Divergent synthesis of thiophene-substituted 1,3,4-oxadiazoles from chloroacrylaldehydes and mercaptoacetyl hydrazides

N′-Arylidenethiophene-2-carbohydrazides were first prepared by the reaction of 3-chloroacrylaldehydes with mercaptoacetylhydrazines. The resulting N′-arylidenethiophene-2-carbohydrazides were converted to the corresponding 1,3,4-oxadiazole derivatives by heating in the presence of iodine. A divergent approach to the synthesis of thiophene-substituted 1,3,4-oxadiazoles was developed.