Sulfonated chitosan-encapsulated HAp@Fe 3 O 4 : an efficient and recyclable magnetic nanocatalyst for rapid eco-friendly synthesis of 2-amino-4-substituted-1,4-dihydrobenzo[4, 5]imidazo[1,2-a]pyrimidine-3-carbonitriles

A one-pot, multi-component, synthetic method for preparation of 2-amino-4-substituted-1,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrimidine-3-carbonitriles has been developed. It was accomplished by mixing 2-aminobenzimidazole, aldehyde and malononitrile in the presence of S-Chit-HAp@Fe3O4 as a nanocatalyst in aqueous medium. The catalyst (S-Chit-HAp@Fe3O4) was synthesized using a co-precipitation method and further characterized by using FT-IR, XRD, FE-SEM, EDX, HR-TEM, TGA and VSM analysis. It was found that the catalyst exhibits magnetic properties and showed high catalytical activity for the synthesis of 2-amino-4-substituted-1,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrimidine-3-carbonitriles. S-Chit-HAp@Fe3O4 nanoparticles catalyzing one-pot, multi-component synthesis of 2-amino-4-substituted-1,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrimidine-3-carbonitriles in aqueous medium has been reported herein.