Eco-friendly heteropoly acid supported on natural clay for the synthesis of calix[4]resorcinarene derivatives

Abstract

The catalytic activity of green catalyst heteropoly-11-tungsto-1-vanadophosphoric acid, H₄[PVW₁₁O₄₀] (HPV) supported on activated natural clay (HPVAC)  has been tested towards the synthesis of calix[4]resorcinarene under solvent-free condition. It is a one-pot multi-component condensation reaction of four moles of aromatic aldehydes with four moles of resorcinol. The advantages of the protocol, solvent-free heterogeneous reaction condition, simple workup procedure, short reaction time, high yield of products and reusability of the catalyst make this method to declare as green approach for synthesis of calix[4]resorcinarene.