Efficient Synthesis of Novel Quinolinone Derivatives via Catalyst-free Multicomponent Reaction

The synthesis of 3-(aryl(piperidin-1-yl)methyl)-4-hydroxyquinolin-2(1H)-one derivatives via catalyst-free multicomponent reaction is described. The reaction of 4-hydroxyquinolin-2(1H)-one, piperidine, and 4-chlorobenzaldehyde was carried out in different solvents and under solvent-free conditions at room temperature. The best solvent in terms of the yield and reaction time was found to be dichloromethane. Most substituted benzaldehydes reacted with 4-hydroxyquinolin-2(1H)-one and piperidine to afford corresponding products in good-to-excellent yields. Aldehydes with electronwithdrawing groups were more reactive to exhibit higher reaction rates. However, 2-substituted benzaldehydes did not react with 4-hydroxyquinolin-2(1H)-one and piperidine under the reaction condition. Aldehydes bearing a hydroxyl group failed to produce the corresponding products.