The N-propylcarbamothioyl benzamide complex of Bi(III) immobilized on silica coated Fe3O4 magnetic nanoparticles has been prepared as a highly effi- cient and recyclable heterogeneous nanocatalyst using simple processes for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones via a one-pot multicomponent condensation reaction of urea, aldehydes and b-dicarbonyl compounds under solvent-free conditions at 100 C. The structural and magnetic properties of the nanocatalyst were characterized using various techniques such as Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, thermogravimetric analysis, vibrating sample magnetometery and elemental analyses. Also, this nanocatalyst can be easily recovered by a magnetic field and reused for subsequent reactions for at least five times without deterioration in catalytic activity.
