Sulfonic Acid-Functionalized Magnetic Nanoparticles as an Efficient Catalyst for the Synthesis of Benzo[4, 5]imidazo[1, 2-a]pyrimidine Derivatives, 2-Aminobenzothia Zolomethylnaphthols and 1-Amidoalkyl-2-naphthols

Background: Carbon-based sulfonated catalysts have several advantages but their separation by filtration is still a challenge. On the other hand, the synthesis of magnetic sulfonated carbon nanoparticle indicated that the magnetic separation could be an efficient way to separate the catalyst from the reaction mixture. Objective: In order to synthesize a separable magnetic Fe3O4@C-SO3H nanoparticle (MNPs) with high catalytic activity in organic transformation, three environmental-benign and low-cost sulfonic acidfunctionalized magnetic nanoparticle (Fe3O4@C-SO3H) were successfully synthesized. Materials and Methods: The Nano catalysts were prepared by solvothermal carbonization of Sucrose (Suc), Starch (Sta) or Cellulose (Cel) in the presence of Fe3O4 Nanoparticle and then grafting of the sulfonic groups on the surface of resulted Fe3O4@C nanoparticles in the presence of p-Toluenesulfonic. Then the Nano catalysts were characterized using XRD, FESEM and FT-IR. Results: Three Fe3O4@C-SO3H were successfully synthesized. The resulted MNPs were used for the synthesis of benzo [4, 5] imidazo[1, 2-a]-pyrimidine derivatives, 2/-aminobenzothiazolomethylnaphthols and 1-amidoalkyl-2-naphthols under solvent-free conditions in excellent yields. It was found that high catalytic activity and easy magnetic separation from the reaction mixture are important achievement with regard to the efficiency and reusability of the catalyst in synthesis. Conclusion: The MNPs were synthesized and used as an efficient catalysts for the one-pot synthesis of benzo [4, 5] imidazo[1, 2-a]-pyrimidine derivatives, 2/-aminobenzothiazolomethylnaphthols, and 1-amidoalkyl-2- naphthols under solvent-free conditions in excellent yields. High catalytic activity and easy magnetic separation from the reaction mixture are two factors for evaluating the performance of Fe3O4@C-SO3H nanoparticles in the organic transformations.