Synthesis of a hercynite supported phosphomolybdic acid magnetic nanocomposite as an efficient catalyst for the synthesis of N-heterocycles

Abstract

In this study, a novel heteropoly acid (HPA) functionalized nanomagnetic catalytic composite was prepared by incorporating phosphomolybdic acid (H₃PMo₁₂O₄₀, PMA) into silica modified hercynite magnetic nanoparticles through a simple post-synthetic modification strategy. The obtained nanocomposite was thoroughly characterized using FT-IR, XRD, TGA-DSC, EDX, ICP-OES, elemental mapping, SEM, TEM, BET, and VSM analyses. The catalytic activity of the resulting heterogeneous catalyst was evaluated in the synthesis of 2,3-dihydroquinazolin-4(1H)-ones through the cyclocondensation of aldehyde or ketone compounds and anthranilamide under reflux conditions, achieving high yields in short reaction times. The key advantage of this catalyst lies in the combination of Brønsted acidity provided by the PMA and the Lewis acidity contributed by both the hercynite support and the PMA. Hot filtration and reusability tests demonstrated that the catalyst remains highly stable and can be reused multiple times without a significant loss in catalytic activity.