A New Procedure for the Preparation of 3,4-dihydropyrimidin-2(1H)-one and Octahydroquinazolinone Derivatives catalyzed by SCMNPs@CA-EASO3H under Solvent-free Conditions

3,4-dihydropyrimidin-2(1H)-one and octahydroquinazolinone derivatives were obtained in high-to-excellent yields and short reaction times using SCMNPs@CA-EA-SO3H as a green and heterogeneous solid acid catalyst in a one-pot multi-component condensation of ethyl acetoacetate or dimedone, urea, and aldehyde compounds under solvent-free conditions. More importantly, the green catalytic system could be easily collected from the reaction solution utilizing an external magnet and reused for five runs with a negligible decrease in yields and reaction rate.