Silica-Supported Dichlorophosphate: a Recoverable Cyclodehydrant for the Eco-Friendly Synthesis of 2,5-Disubstituted 1,3,4-Oxadiazoles under Solvent-Free and Microwave Irradiation Conditions

A series of symmetrical and unsymmetrical 2,5-disubstituted 1,3,4-oxadiazoles were efficiently synthesized from the cyclodehydration of diacylhydrazines by using silica-supported dichlorophosphate as a recoverable cyclodehydrant in solvent-free medium under microwave irradiation. This protocol has advantages of no corrosion, no environmental pollution, accelerated rate, high yield and simple work-up procedure.