Synthesis of 4,4’-(Arylmethylene)bis(1H-pyrazol-5-ols) Using Silica-bonded Ionic Liquid as Recyclable Catalyst

Abstract

N-(3-Silicapropyl)-N-methyl imidazolium hydrogen sulfate ([Sipmim]HSO4) is prepared and employed as a recyclable catalyst for the synthesis of 4,4’-(arylmethylene)bis(1H-pyrazol-5-ols) from aromatic aldehydes with 3-methyl-l-phenyl-5-pyrazolone in refluxing ethanol. [Sipmim]HSO4 could be recycled for several times without any additional treatment.