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[PVVW11O40] (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
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.