Urea hydrogen peroxide-initiated synthesis of pyranopyrazoles through oxidative coupling under base- and metal-free conditions by physical grinding method

Abstract

A novel multicomponent one-pot expeditious synthesis of highly functionalized and pharmaceutically fascinated pyranopyrazoles has been developed. This reaction occurs via tandem Knoevenagel condensation reaction of methyl aryl derivatives, 3-methyl pyrazolone and malononitrile in the presence of urea hydrogen peroxide under the physical grinding method. The present methodology offers several benefits such as available green and cheap starting materials, solvent-free, mild reaction conditions, high atom economy, eco-friendly standards, excellent yields and easy isolation of the products without column chromatographic separation. Graphic abstract: [Figure not available: see fulltext.]. © 2021, The Author(s), under exclusive licence to Springer Nature Switzerland AG.