A Simple and Efficient Method for the Synthesis of Benzo[3,4-a]Phenazin-5-Ols and Benzo[f]Pyrido[b]Quinoxalin-5-ol Derivatives Using Trisodium Citrate as an Efficient Organo-Catalyst at Room Temperature

Abstract

A simple, convenient, efficient and environmentally benign method has been developed for the synthesis of benzo[3,4-a]phenazin-5-ol as well as benzo[f]pyrido[2,3-b]quinoxalin-5-ol derivatives via the condensation of lawsoneand o-phenylenediamines or pyridine-2,3-diamines respectively by using a catalytic amount of trisodium citrate as an efficient, commercially available and low cost organo-catalyst in aqueous ethanol at room temperature. Mild reaction conditions, use of metal-free organocatalyst, nontoxic solvent, energy efficiency, no column chromatographic separation, gram scale production and reusability of the catalyst containing solvent media are some of the notable advantages of our developed protocol.