FeCl3-PROMOTED SYNTHESIS OF 2,5-DISUBSTITUTED 1,3,4- OXADIAZOLES FROM ARYLHYDRAZIDES AND ARYLIDENE MELDRUM’S ACIDS VIA OXIDATIVE BOND CLEAVAGE FOR SUSTAINABLE CHEMICAL PROCESSES

A novel synthetic strategy for the preparation of 2,5-disubstituted 1,3,4-oxadiazoles has been developed using FeCl₃ as a catalyst. Conveniently, several 1,3,4-oxadiazoles that are 2,5-disubstituted, both symmetrical and asymmetrical, can be produced in an efficient and adaptable fashion by condensation of arylhydrazides with arylidene Meldrum’s acid via iron mediated oxidative cleavage of arylidene Meldrum’s acid using DMSO as oxidant and solvent. This process is compatible with both aromatic and aliphatic arylidene Meldrum’s acids. Other benefits of this process include good yields, high functional group tolerance, low cost of catalyst, and phasing out hazardous chemicals. This new synthetic route has significant potential for applications in drug development and material science and presents an environmentally benign alternative for producing heterocyclic compounds.