Design and characterization of a thiazolo-pyrimidin-amine functionalized Fe3O4@SiO2@GLYMO nanocatalyst for green synthesis of 2-amino-3-cyano-4H-pyran derivatives

Abstract

In this work, a new magnetically separable nanocatalyst, Thiazolo-pyrimidin-amine functionalized Fe₃O₄@SiO₂@GLYMO (Fe₃O₄@SiO₂–Gly–ThzPyrAm), was successfully designed and synthesized in accordance with green chemistry strategies. The catalyst was characterized by FT-IR spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and vibrating sample magnetometry (VSM), providing complementary evidence for its chemical functionalities, morphology, elemental composition, and magnetic properties. The prepared nanocatalyst exhibited outstanding catalytic activity for the green synthesis of 2-amino-3-cyano-4H-pyran derivatives via a one-pot Knoevenagel–Michael–cyclization reaction involving aldehydes, dimedone, and malononitrile. A wide variety of the desired products were obtained within 35 min in excellent isolated yields (92–98%) under mild reaction conditions. Moreover, the magnetic catalyst was readily separated from the reaction mixture with the aid of an external magnet and retained its catalytic efficiency over at least five consecutive cycles with only a slight reduction in activity. The combination of operational simplicity, high catalytic efficiency, magnetic recoverability, and reusability highlights the potential of this catalytic system as a sustainable and efficient platform for environmentally friendly organic synthesis.