An efficient, green and ecofriendly procedure has been developed using Fe3O4@SiO2–imid–PMAn as a
magnetic catalyst for a rapid and improved synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted
imidazoles under solvent-free conditions and microwave irradiation in excellent yields. The reactions
under conventional heating conditions were compared with the microwave-assisted reactions. The
operational simplicity, practicability and applicability of this protocol to various substrates make it an
interesting alternative to previous procedures. The present approach offers several advantages such as
short reaction times, high yields, simplicity of operation, easy work-up, a cleaner reaction and ease of
recovery and reusability of the catalyst using a magnetic field. Also, the nanocatalyst can be easily
recovered by the application of a magnetic field and reused for the next reactions at least 5 times
without distinct deterioration in catalytic activity. SEM, BET, DLS and leaching of the catalyst after each
reaction cycle were investigated.
