Nanomagnetically modified polyphosphoric acid (NiFe2O4@SiO2–PPA): an efficient, fast, and reusable catalyst for the synthesis of 2-thioxoquinazolinones under s
文摘
Polyphosphoric acid functionalized silica-coated magnetic nanoparticles with core–shell structure (NiFe2O4@SiO2–PPA) has been used as a magnetically recyclable green catalyst for the one-pot three-component synthesis of 2-thioxoquinazolinones by the reaction of isatoic anhydride, primary amines and thiourea under neat conditions. The catalyst is readily recovered by simple magnetic decantation and can be recycled five times with no significant loss of catalytic activity. Keywords Polyphosphoric acid Magnetic nanoparticles One-pot, three-component 2-Thioxoquinazolinones Isatoic anhydride