An efficient and eco-friendly procedure for the synthesis of 2,3-dihydroquinazolin-4(1H)-
ones and spiroquinazolinones in the presence of sulfuric acid functionalized silica-coated magnetite
nanoparticles under solvent-free conditions has been described. The reactions are completed in short
times, and the products are obtained in high isolated yields without any undesirable side reaction. This
method has several advantages, including short reaction time, facile operation, easy work-up, ecofriendly
reaction conditions, high isolated yields, and reusability of the catalyst. The catalyst could be
easily separated and recovered from the reaction mixture by an external magnet and reused in subsequent
reactions with no considerable loss in activity.