Research Article

Superparamagnetic Iron Oxide as an Efficient Catalyst for the One-Pot, Solvent-Free Synthesis of 5,5-Disubstituted Hexahydropyrimidines and Their Spiro Analogues

Table 2

Comparison of various types of catalysts used for the synthesis of hexahydropyrimidines with our catalyst.

EntryCatalyst (5 mol %)Time (h)Yield (%) (isolated)

1AlCl3640
2ZnCl2625
3Fe3O42.590
4SnCl2630
5AcOH651
6H3BO3633
7HCl6