An Efficient One-pot Synthesis of Pyrazolone Derivatives Promoted by Acidic Ionic Liquid

A new class of pyrazolone derivatives has been isolated in good to excellent yields from the 2 ： 1 condensation reaction between 3-methyl-1-phenyl-5-pyrazolone and arylaldehydes in the presence of ionic liquid [HMIM]HSO4. The compounds were characterised by their IR, NMR spectra, MS and elemental analyses. The important features of the methodology are a wide application range of substrates, higher yields and shorter reaction time.