An expedient and eco-friendly approach for multicomponent synthesis of dihydropyrano[2,3-c]pyrazoles using nano-Al₂O₃/BF₃/Fe₃O₄ as reusable catalyst

Abstract

The pyranopyrazole derivatives have many biological activities. They were synthesized via a four-component coupling of aromatic aldehyde, malononitrile, ethyl acetoacetate and hydrazine hydrate. In this study, dihydropyrano[2,3-c]pyrazoles have been synthesized in the presence of nano-Al₂O₃/BF₃/Fe₃O₄ as catalyst in water/ethanol under reflux conditions. The catalyst was removed from the mixture of reaction by an external magnet and was reusable for several times without any loss of its activity. The obtained pyranopyrazoles were characterized by various methods such as FT-IR, ¹HNMR and melting point. Easy purification, clean and convenient procedure are some advantages of this method.

Graphical Abstract

Keywords:

• Nano-Al₂O₃/BF₃/Fe₃O₄
• pyranopyrazole
• magnetic catalyst
• Lewis acid
• multicomponent reaction

Additional information

Funding

The Research Council of Yazd University is gratefully acknowledged for financial support of this work.