One-pot sonochemical synthesis of benzopyranophenazines using nano Fe3O4@ PAA-SO3H

Abstract

A proper, atom-economical, straightforward one-pot multicomponent synthetic route for the synthesis of benzopyranophenazines has been presented by the reaction of hydroxynaphthoquinone, <em>o</em>-phenylenediamine, benzaldehydes, and malononitrile with crosslinked sulfonated polyacrylamide (Cross-PAA-SO₃H) attached to nano-Fe₃O₄as an efficient heterogeneous solid acid catalyst under ultrasonic irradiations in ethanol. Experimental simplicity, wide range of products, excellent yields in short reaction times and applying the sonochemical methodology as an efficient method and innocuous means of activation in synthetic chemistry for the preparation of medicinally privileged heterocyclic molecules are some of the important features of this method. The present catalytic procedure is extensible to a wide diversity of substrates for the synthesis of a variety-oriented library of benzopyranophenazines.