Ionic Liquid 4-(3-Methyl-1-imidazolio)-1-butanesulfonic Acid Hydrogen Sulfate-catalyzed Synthesis of Phthalazinetrione Derivatives

Abstract

A simple method for the synthesis of phthalazinetrione derivatives by a one-pot three-component condensation reaction of phthalhydrazide, 1,3-dicarbonyl compounds and aldehydes catalyzed by the ionic liquid 4-(3-methyl-1-imidazolio)-1-butanesulfonic acid hydrogen sulfate ([BSO 3 HmIm]HSO 4 ) is reported. Good to excellent yields were obtained in short reaction times in the solvent PEG 600 (polyethylene glycol 600) at 120 • C. The strategy proved to be efficient and environmentally benign. The catalyst/solvent system could easily be recovered and reused for at least 5 times without noticeable loss of activity.