Magnetite Polycitric Acid (Fe3O4@PCA) Nanoparticles: A Novel, Efficient and Reusable Solid Acid Catalyst for the Preparation of Polyhydroquinolines

Background: Polyhydroquinoline derivatives are known as one of the most significant class of biologically active heterocycles. Herein, in this paper, magnetite polycitric acid (Fe3O4@PCA) nanoparticles as novel, efficient and reusable catalysts were used for the preparation of polyhydroquinoline derivatives. Method: Using aromatic and heteroaryl aldehydes with dimedone, ammonium acetate and ethyl acetoacetate, polyhydroquinoline derivatives could be synthesized under solvent-free microwave irradiation condition by Hantzsch multi-component reactions. Results: Polyhydroquinoline derivatives were prepared under optimized reaction conditions in excellent yield (97%). The reaction mechanism has been investigated. Conclusion: This method has the advantages of short reaction times, use of an economically convenient catalyst, and excellent product yields. Furthermore, the catalyst could be recycled and average chemical yield for seven consecutive runs was 92%, without any significant reduction of activity.