Sustainable and green synthesis of 3-methyl-4-arylmethylene-isoxazole-5 (4H)-one derivatives under mild conditions using a novel phosphoric acid-based molten salt as catalyst

In this work, pyrrolidinium dihydrogen phosphate ([H-Pyrr][H2PO4]) was prepared as a novel green molten salt from cheap and commercially available starting materials with a very simple method and identified by various methods including FT-IR and NMR techniques. In continue, this reagent was used as a recyclable and effective catalyst in the synthesis of bioactive potent 3-methyl-4-arylmethylene-izoxazole-5(4H)-one derivatives. Use of green solvent and reagent, ease of manufacturing of the catalyst, high product yields, short reaction times, reusability of the catalyst and cost-effectiveness are some of the advantages of this method.