One-pot, four-component synthesis of fully substituted 1,3,4-oxadiazole derivatives from N-isocyaniminotriphenylphosphorane (Ph3PNNC), a primary amine, a carboxylic acid and cinnamaldehyde

The imine intermediate generated by the addition of primary amine to cinnamaldehyde is trappedby N-isocyaniminotriphenylphosphorane (Ph3PNNC) and a carboxylic acid, and leads to theformation of the corresponding iminophosphorane intermediate. 1,3,4-Oxadiazole derivatives areformed via intramolecular aza-Wittig reaction of the iminophosphorane intermediate. Thereactions were completed under neutral conditions at room temperature. The fully substituted1,3,4-oxadiazole derivatives were produced in high yields. The method offers a mild, simple, andefficient route for the preparation of fully substituted 1,3,4-oxadiazols. The structures of theproducts were deduced from their IR, 1H NMR, 13C NMR spectra, and massspectrometry.Keywords: Baclofen; synthesis; GABA receptor; γ-aminobutiric acid.

Keywords:

N-Isocyaniminotriphenylphosphorane , cinnamaldehyde , carboxylic acids , 1 , 3 , 4-oxadiazole , aza-Wittig reaction