Four-Component Synthesis of Functionalized 1,3,4-Oxadiazole Derivatives Bearing the 2-Amino benzothiazole Moiety

Abstract

A one-pot eighteen derivatives of N-((5-(aryl)-4H-pyrazol-3-yl)(aryl)methyl)benzo[d]thiazol-2-amine (5a-r) were synthesized from 2-aminobenzothiazole, aromatic aldehyde, N-isocyaniminotriphenylphosphorane on reaction with aryl carboxylic acid derivatives under a catalyst-free condition in CH2Cl2 by a Ugi-4CR/aza-Wittig cyclization at room temperature in fairly good yields (except for 5r, in which the aldehyde used has an electron-donating group). The newly synthesized compounds were confirmed and deduced based on IR, 1 H NMR, 13 C NMR, and mass spectroscopy, and elemental analysis.