علیرضا حسنی نژاد

Inthiswork,novelionicliquid1-sulfopyridiniumchloride{[Pyridine–SO3H]Cl}issynthesized,andcharacterized by IR, 1H and 13C NMR, UV as well as mass spectra. The ionic liquid is used as an ef?cient, homogeneousandreusablecatalystforthesynthesisof4,4-(arylmethylene)-bis(3-methyl-1-phenyl-1Hpyrazol-5-ol)s by tandem Knoevenagel–Michael reaction of 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one with various aromatic and hetero-aromatic aldehydes under mild reaction conditions.