Copper triflate-mediated synthesis of 1,3,5-triarylpyrazoles in [bmim][PF6] ionic liquid and evaluation of their anticancer activities

Abstract

A simple, efficient, and environment friendly protocol for the synthesis of 1,3,5-triarylpyrazoles and 1,3,5-triarylpyrazolines in [bmim][PF₆] ionic liquid mediated by Cu(OTf)₂ is described. The reaction protocol gave 1,3,5-triarylpyrazoles in good to high yields (71–84%) via a one-pot addition–cyclocondensation between chalcones and arylhydrazines, and oxidative aromatization without the requirement for an additional oxidizing reagent. The catalyst can be reused for up to four cycles without much loss in the catalytic activity. The pyrazoles (4a–o) and pyrazolines (3a–n) were evaluated for their antiproliferative activity in SK-OV-3, HT-29, and HeLa human cancer cells lines. Among all the compounds, 3b inhibited cell proliferation of HeLa cells by 80% at a concentration of 50 μM.