Two Novel Pyrazole Derived Ionic Liquids Based on Chloride and Trichlorostannate Anions: Preparation, Characterization, and Evaluation of Their Catalytic Activity in the Synthesis of 1H-Pyrazolo[1,2-b]phthalazine-5,10-diones

Abstract

Abstract Two novel room-temperature disulfonic acid functionalized ionic liquids derived from 3,5-dimethyl-1 H -pyrazole consisting of chloride and trichlorostannate anions, 3,5-dimethyl-1,2-disulfonic acid-1 H -pyrazolium chloride and 3,5-dimethyl-1,2-disulfonic acid-1 H -pyrazolium trichlorostannate, have been synthesized, characterized and evaluated for their catalytic efficiency in the synthesis of 1 H -pyrazolo[1,2- b ]phthalazine-5,10-diones by the one-pot, three-components reaction of phthalhydrazide, an aromatic aldehyde and malononitrile or ethyl cyanoacetate under solvent-free conditions. The results have demonstrated high catalytic activity of these novel ionic liquids containing acidic SO 3 H groups in producing high yields of the desired products in short reaction time. The ionic liquids can be used at least four times without any noticeable decrease in catalytic activity.