Ultrasound Assisted Synthesis of 2-Amino-5-aryl-1,3,4-oxadiazoles from (diethoxymethyl)benzene Derivatives

A new method has been developed through the reaction of substituted (diethoxymethyl)benzene with hydrazine carboxamide followed by intramolecular cyclization in the presence of DBDMH (1,3-Dibromo-5,5-dimethylhydantoin) to provide desired 2-amino-1,3,4-oxadiazoles. The reaction proceeded smoothly under ultrasound irradiation at 70?C and produced corresponding 2-amino-1,3,4-oxadiazoles 3(a-i) in excellent yields. This approach has various benefits over the classical-conventional method, including a high yield, a shorter reaction time, and a greener synthesis strategy with tolerance of various functional groups..