Synthesis of 3-(benzylideneamino)-2-phenyl-5H-imidazo[1,2-b]pyrazole-7-carbonitriles via a four-component condensation reaction

A direct and efficient approach for the synthesis of a new series of 3-(benzylideneamino)-2-phenyl-5H-imidazo[1,2-b]pyrazole-7-carbonitriles has been developed through a sequential one-pot, four-component condensation reaction of easily available aromatic aldehydes, toluene-4-sulfonylmethyl isocyanide (TsCH2NC), and 5-amino-1H-pyrazole-4-carbonitrile. The reaction was performed in the presence of p-toluenesulfonic acid as a catalyst at room temperature in acetonitrile as a solvent. Products were obtained in moderate to high yields.