4. Conclusions
We have prepared a novel magnetic catalyst containing
Preyssler HPA supported on silica coated nickel ferrite NPs
(NFS‐PRS) for the synthesis of bis(dihydropyrimidinone)ben‐
zene and 3,4‐dihydropyrimidin‐2(1H)‐ones and ‐thiones deriv‐
atives by the Biginelli reaction. The Preyssler HPA provided
adequate acidic sites to give the excellent catalytic activity of
NFS‐PRS. This magnetic catalyst can be easily removed from
the reaction mixture by an external magnet, and it was reused
several times without loss of catalytic activity. In addition to the
synthesis of these products by the Biginelli reaction, the envi‐
ronmentally benign NFS‐PRS catalyst is potentially promising
for other acid‐catalyzed chemical reactions