A One Pot, Solvent Free and Catalyst Free Synthesis of Substituted 2-Amino-5-Aryl-1,3,4-Oxadiazoles under Microwave Irradiation
A convenient one-pot, multi-component and solvent free procedure for the preparation of substituted 2-amino-5-aryl-1,3,4-oxadiazoles has been achieved. The method is a significant improvement over previously reported synthesis. Reaction of acid chlorides with hydrazine hydrate and isothiocynates under microwave-irradiation (MWI) afforded the corresponding 1,3,4-oxadiazole derivatives in high yields with high purity. All synthesized compounds were characterized by FT-IR, proton and carbon NMR, mass spectroscopy and elemental analysis. A possible mechanism is proposed for the cyclodesulfurization based on the results of this study.
Mass spec analysis was performed on the Advion expression Compact Mass Spectrometer (CMS) using electrospray ionization (ESI).