Green sonosynthesis of phenazinpyrimidines using Co3O4 / ZnO @ N‐GQDs @ SO3H nanocomposite as a robust heterogeneous catalyst

SO3H functionalized Co3O4/ZnO@N‐GQDs nanocomposite as a green heterogeneous solid acid catalyst has been utilized for the synthesis of phenazinpyrimidines by the four‐component reaction of 2‐hydroxy‐1,4‐naphthaquinone, o‐phenylenediamine, aldehydes, and 6‐amino‐1,3‐dimethyluracil under ultrasonic irradiations. The catalyst has been characterized by Fourier‐transform infrared spectroscopy, scanning electron microscope, X‐ray powder diffraction, energy‐dispersive X‐ray spectroscopy, thermogravimetric analysis, Brunauer–Emmett–Teller, and vibrating‐sample magnetometer). This method provides several benefits, including excellent yields in short reaction times, wide range of products, and applying the sonochemical methodology as efficient method.