Copper(ii) ionic liquid catalyzed cyclizationaromatization of hydrazones with dimethyl acetylenedicarboxylate: a green synthesis of fully substituted pyrazolesElectronic supplementary information (ESI) available: Full characterization data for compounds and crystallographic data for compound 4h. CCDC 867509. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c3nj40756j

The Lewis acid room temperature ionic liquid, [ n -Bu 4 P][CuBr 3 ], was found to be an efficient and reusable catalyst for three component synthesis of fully substituted pyrazoles from the reaction of aldehydes, arylhydrazines and dimethyl acetylenedicarboxylate (DMAD). This catalytic system is simple and chemoselective with high yields. The Lewis acid room temperature ionic liquid, [ n -Bu 4 P][CuBr 3 ], was found to be an efficient and reusable catalyst for three component synthesis of fully substituted pyrazoles.