Unexpected one pot pseudo four-component reaction for the synthesis of (10E)-N-benzylidene-2-phenylH-imidazo [1,2-a]pyridin-3-amine derivatives under solvent-free conditions

This work described an efficient Pseudo four-component synthesis of (10E)-N-benzylidene-2-phenylH-imidazo[1,2-a]pyridin-3-amine derivatives from 2-aminopyridin, malononitrile and arylaldehydes in the presence of NaOH under solvent-free and conventional heating condition in good to excellent yields. A wide range of aromatic aldehydes would easily undergo condensations with 2-aminopyridin and malononitrile under solvent-free conditions in order to afford the desired products of good purity in excellent yields. For optimization of this reaction, the effect of NaOH amounts and use of other bases such as Et3N and Na2CO3 instead of NaOH and the efficacy of time and temperature to the reaction yields were studied. The use of simple and readily available starting materials, pharmacologically interest product, short reaction times, and applications in bioorganic and medicinal chemistry are the main advantages of this reaction.