Fe ₃ O ₄ @SiO ₂ @taurine: a magnetically recoverable green nanocatalyst for efficient synthesis of pyrano[2,3- d ]pyrimidine derivatives

The development of recyclable and eco-friendly catalysts for heterocyclic synthesis remains a central theme in sustainable chemistry. Here, we present a magnetically recoverable Fe₃O₄@SiO₂@taurine catalyst, prepared by sequential silica coating and taurine functionalization of Fe₃O₄ nanoparticles. Structural, morphological, and magnetic characteristics were established through FT-IR, XRD, TEM, SEM-EDS, TGA, BET and ZETA analyses. This catalytic system promotes a one-pot, three-component reaction of aromatic aldehydes, malononitrile, and barbituric or thiobarbituric acid in aqueous ethanol under reflux, affording pyrano[2,3-d]pyrimidine derivatives in high yields and short reaction times. Ease of magnetic recovery, operational simplicity, and stable activity over multiple cycles highlight its practical applicability. Collectively, these findings demonstrate Fe₃O₄@SiO₂@taurine as a green, efficient, and recyclable platform for sustainable organic transformations.