Ionic liquid catalyzed one pot green synthesis of isoxazolone derivatives via multicomponent reaction

A series of 3-methyl-4-((3-aryl-1-phenyl-1H-pyrazol-4-yl)methylene)isoxazol-5(4H)-one derivatives have been efficiently synthesized by environmentally benign, one-pot three component condensation of substituted 1,3-diaryl-1H-pyrazole-4-carboxyaldehyde, beta-keto ester and hydroxyl amine hydrochloride in the presence of ionic liquid [HNMP][HSO4] as a catalyst in ethanol. These derivatives have been synthesized by conventional, ultrasound and microwave irradiation methods. The combination of ionic liquid with ultrasound as well as microwave irradiation makes the protocol fascinating and environmentally benign. In addition, it has several benefits such as simple work-up procedure, clean reaction profile, short reaction time and good yields.