Preparation of Polyhydroacridines and Polyhydroquinolines Using BPHSBF as a Novel Organic–Inorganic Hybrid Magnetic Nanocatalyst

Initially, 1,3-bis(4-pyridyl)propane hydrogen sulfate grafted to chloropropyl functionalized bilayer silica-nano-Fe₃O₄ (BPHSBF) has been synthesized. The resulting nanocomposite has been characterized by Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FE SEM), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), thermal gravimetric analysis (TGA), Brunauer–Emmett–Teller (BET) and X-ray diffraction (XRD) analyses. Afterward, polyhydroacridines and polyhydroquinolines were produced in a one-pot multicomponent synthesis (via Hantzsch reaction) in the presence of our magnetic nanocatalyst and in a solvent-free environment. Some of the key characteristics of this protocol are atom economy, high yields, very suitable turnover number (TON) and turnover frequency (TOF) values, simple work-up, environmental friendliness, simplicity in separating the catalyst by an external magnet, and mild reaction conditions. Furthermore, in both synthetic protocols, the heterogeneous nature of BPHSBF was investigated and affirmed by utilizing the hot filtration technique and its remarkable recyclability and reusability in 6 runs. Graphical Abstract: (Figure presented.)