Preyssler heteropoly acid supported on silica coated NiFe2O4 nanoparticles for the catalytic synthesis of bis(dihydropyrimidinone)benzene and 3,4‐dihydropyrimidin‐2(1H)‐ones

Abstract

A novel magnetic acidic catalyst comprising Preyssler (H14[NaP5W30O110]) heteropoly acid supported on silica coated nickel ferrite nanoparticles (NiFe2O4@SiO2) was prepared. The catalyst was characterized by Fourier transform infrared, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, energy dispersive spectrum, VSM and particle size neasurement. Its catalytic activity was investigated for the synthesis of bis(dihydropyrimidinone)benzene and 3,4-dihydropyrimidin-2(1H)-ones derivatives by the Biginelli reaction. With the catalyst, the reactions occurred in less than 1 h with good to excel-lent yields. More importantly, the catalyst was easily separated from the reaction mixture by an external magnet and reused at least five times without degradation in the activity.