A practical one pot synthesis of novel 2-hydroxy-4-chromanone derivatives from 3-formylchromone

Abstract

A one pot synthesis of 4-chromanone derivatives (5a–j) is described using Zn[(L)(Proline)]2 as catalyst in aqueous media. The compounds have been characterized on the basis of elemental and spectral data (IR, 1H NMR and mass). The advantages of this protocol include high yields, mild reaction conditions, environmentally benign and simple operational procedure. The use of water as solvent and Zn[(L)proline]2 as recyclable, non-toxic catalyst make such synthesis a truly green process. An ecofriendly synthetic route has been developed for the synthesis of 2-hydroxy-4-chromanone derivatives (5a–j) in excellent yields employing 3-formylchromone (1) and primary aromatic amines (2a–j) in the presence of non-toxic, green Zn[(L)proline]2 catalyst in water. The catalyst is recyclable and shows activity up to three cycles.