Ionic liquid under ultrasonic irradiation towards a facile synthesis of pyrazolone derivatives

Ionic liquid [HMIM]HSO4 was found to be an efficient catalyst for the synthesis of 4-[(5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)-phenyl-methyl]-5-methyl-2-phen-yl-1,2-dihydro-pyrazol-3-ones through the condensation reaction of arylaldehydes and 3-methyl-1-phenyl-5-pyrazolone under ultrasonic irradiation at room temperature. The present methodology offers several advantages such as excellent yields, simple procedure and mild conditions.