Nanomagnetic-supported sulfonic acid is found to be a new, powerful, and reusable heterogeneous
catalyst for the rapid synthesis of 3,4-dihydropyrimidin-2-(1H)-ones under conventional heating and
microwave irradiation. This is the first example of combination of magnetic iron nanoparticles
and microwave technique for the multicomponent reaction. The optical behaviors of the
3,4-dihydropyrimidin-2-(1H)-ones have been investigated by UVevis spectroscopy