Bis(p-sulfoanilino)triazine-functionalized silica-coated magnetite nanoparticles as an efficient and magnetically reusable nano-catalyst for Biginelli-type reaction

The preparation of bis(p-sulfoanilino)triazine-functionalized silica-coated magnetite nanoparticles and their use as a novel magnetically separable nanocatalyst for the synthesis of various Biginelli adducts are presented. The materials were characterized by various microscopic and spectroscopic techniques such as scanning electron microscopy, vibrating sample magnetometer, X-ray powder diffraction, and FT-IR spectroscopy, etc. A series of 3,4-dihydropyrimidinones or thione products were conveniently prepared by this green protocol from the reactions of aromatic aldehydes with the 1,3-dicarbonyl compounds and urea or thiourea using the catalyst under solvent-free conditions. The present method is operationally simple and offers several advantages such as good to excellent yields, short reaction times, the absence of a solvent, and simple work-up. Moreover, the aforementioned nanocatalyst can be easily recovered from the reaction mixture with the assistance of an external magnetic field and reused several times without any loss of its catalytic activity. [GRAPHICS] .