A novel copper-based magnetic nano catalyst for the synthesis of hexahydroquinolines, aminocyanopyridines, and pyranopyrazoles

A novel copper-based magnetic nanocatalyst, MNP@Im-Cu, was successfully synthesized via a six-step procedure. Its structural evolution, magnetic behavior, and thermal stability were systematically characterized using Fourier-transform infrared spectroscopy (FT-IR), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis/differential thermal analysis (TGA/DTA), vibrating-sample magnetometry (VSM), inductively coupled plasma analysis (ICP), and X-ray diffraction (XRD). These analyses confirmed successful surface functionalization, uniform core-shell morphology, elemental homogeneity, magnetic properties, and thermal robustness. The catalytic efficiency of this multifunctional nanocatalyst was demonstrated in the one-pot, four-component synthesis of pharmaceutically relevant heterocycles: hexahydroquinolines (HHQs), 2-amino-3-cyanopyridines (ACPs), and pyranopyrazoles (PYPYs). Reactions proceeded under solvent-free conditions using readily available starting materials, affording the desired products in high to excellent yields with notably short reaction times. The catalyst exhibited excellent reusability and chemo-selectivity, underscoring its potential as a sustainable and efficient platform for multi-component heterocycle synthesis.