Magnetic nanohybrids of folic acid as green biocatalysts for the synthesis of heterocyclic compounds

Abstract

In the first part of this study, magnetic nanoparticles were decorated with folic acid (Vitamin B9) under ultrasonic agitation in water, resulting in heterogeneous nano-biocatalysts (FA@γ-Fe2O3), which were characterized using different techniques, such as VSM, FT-IR, and FESEM. The efficiency of the as-prepared magnetic nanocatalyst was assessed in the synthesis of quinoxaline derivatives. In the second part, a Cu (II) folic acid complex was used for modifying the surface of γ-Fe2O3 (FA-Cu@γ-Fe2O3). It was used successfully in several different transformations in a one-pot reaction sequence, including the aerobic oxidation of benzylic alcohols to aldehydes and the tandem synthesis of benzimidazoles through the dehydrogenative coupling of primary benzylic alcohols and aromatic diamines. The biocatalysts maintained their efficiency and structural integrity after 4 runs, which confirmed that components are firmly bonded. The advantages of these catalytic systems include easy separation and reusability of the solid catalyst for subsequent rounds of reactions with an external magnet, demonstrating great potential for practical applications.