Pumice supported perchloric acid catalyzed synthesis of isoxazole-5(4H)-one derivatives under reflux conditions using water as a green solvent

A highly efficient and green synthetic protocol was developed for the synthesis of isoxazol-5(4H)-ones through a one-pot condensation of aromatic aldehydes, ethyl acetoacetate, and hydroxylamine hydrochloride in the presence of a Pumice@HClO4 catalyst under reflux conditions in water as the green solvent. Water is an inexpensive, non-flammable, environmentally benign, and non-carcinogenic solvent, making it an attractive alternative to hazardous organic solvents. The major advantages of the present method include its environmentally friendly nature, shorter reaction time, use of green solvent, and high atom economy. The Pumice@HClO4 catalyst exhibited remarkable catalytic activity for synthesis of isoxazolone derivatives. The structures of synthesized isoxazolone derivatives were characterized by 1H NMR, 13C NMR and mass spectrometry.