Mechanochemical Synthesis of 2,5-Disubstituted 1,3,4-Oxadiazoles Mediated by PPh3-TCCA

Abstract Mechanochemical synthesis of 2,5-disubstituted 1,3,4-oxadiazoles was developed as an environmentally benign alternative to conventional solvent-based methods. In the presence of triphenylphosphine and trichloroisocyanuric acid, N-acylbenzotriazoles condense with acylhydrazides leading to oxadiazoles derivatives in good to excellent yields within minutes. The approach circumvents the need for strictly anhydrous conditions, external heating, long reaction times, as well as tedious multistep procedures. A range of substrates with reactive functionalities was also well tolerated.