Preparation and Application of Fe3O4@SiO2@OSO3H Nanocomposite as a Green Catalyst for the Synthesis of Octahydroquinazolinones

In this research the magnetite nanoparticles supported silica sulfonic acid (Fe3O4@SiO2@OSO3H) was used as a green and efficient catalyst for the preparation of octahydroquinazolinone derivatives as biologically active heterocyclic compounds. This procedure avoids hazardous reagents, solvents, catalyst and can be an eco-friendly alternative to the existing methods. The one-pot three-component reaction of aldehydes, dimedone and urea or thiourea has several advantages such as: simple procedure, eco-friendly approach, excellent yields, short reaction times, little catalyst loading, simple purification and facile catalyst separation. In addition, the synthesis and application of Fe3O4@SiO2@OSO3H nanocomposite as a robust and recoverable heterogeneous nanocatalyst is described. Fe3O4 nanoparticles encapsulated-silica particles bearing sulfonic acid were readily recovered using an external magnet and could be reused several times without significant loss of its reactivity. The catalyst was fully characterized by different spectroscopic techniques including VSM, FT-IR, SEM, XRD, EDX and TEM analysis.