Organocatalyzed three-component synthesis of isoxazol-5(4h)-ones under aqueous conditions

Abstract

The three-component cyclocondensation was performed using various frequently available aryl/heteroaryl aldehydes, hydroxylamine hydrochloride, and β-ketoesters in water as a green reaction medium at 80 °C. In this reaction, isoxazol-5(4H)-ones were obtained in the presence of 2-aminopyridine as an efficient and low-cost organocatalyst. The present methodology offers sustainable approach with appreciable yields of the desired heterocycles. This procedure has expectant features, including shorter reaction times, easy separation of pure products, avoiding the hazardous organic solvents, simplicity experimental procedure, operationally simple, and eco-friendly. The heterocyclic structures were characterized using physical properties and analysis of spectral data.