Synthesis and Characterization of Some 1,3,4-oxadiazole derivatives

Abstract

Reactions of N-isocyaniminotriphenylphosphorane with cyclopentanone have been studied in the presence of aromatic carboxylic acids and primary amines. The reactions were proceeded smoothly at room temperature under neutral conditions in order to afford sterically congested 1,3,4-oxadiazole derivatives by an intramolecular Aza-Wittig cyclization in dichloro methanein excellent yields. The structures of the products were deduced from their IR, Mass, ¹H NMR, and ¹³C NMR spectra. The method offers a mild, simple, and efficient route for the preparation of fully substituted1,3,4-oxadiazoles from cyclopentanone, primaryamines, N- isocyaniminotriphenylphosphorane and aromatic carboxylic acids. Easy work-up, high yields and fairly mild reaction conditions make it a useful procedure in comparison to the modern synthetic methodologies.