One-pot three-component synthesis of bis(indolyl)methanes under solvent-free condition using heteropoly-11-tungsto-1-vanadophosphoric acid supported on natural clay as catalyst

ABSTRACT

One-pot three-component condensation reaction of two moles of indole and one mole of aromatic aldehyde for the synthesis of bis(indolyl)methanes in the presence of new catalytic material, heteropoly-11-tungsto-1-vanadophosphoric acid, H₄[PV^VW₁₁O₄₀] (HPV) supported on activated natural clay under solvent-free reaction condition has been proposed. The catalysts were prepared by incipient wetness impregnation method. The physicochemical characterizations of the HPV (20%) supported on natural clay (HPVAC-20) have also been discussed. Solvent-free heterogeneous reaction condition, simple workup procedure, short reaction time, high yield of products, and reusability of the catalyst are the advantages of the protocol.

GRAPHICAL ABSTRACT

KEYWORDS:

• Bis(indolyl)methanes
• heteropoly acid
• natural clay
• solvent-free

Acknowledgments

The authors Ponnusamy Sami and Karuppaiah Selvakumar thank University Grants Commission, New Delhi, India, for the award of major research project (F. No. 42-349/2013(SR)) and financial assistance. We also thank Managing Board, Virudhunagar Hindu Nadars’ Senthikumara Nadar College (Autonomous), Virudhunagar, for infrastructural facilities.