Green Synthesis of Imidazopyridine Tetracyclic Derivatives via the Groebke-Blackburn- Bienaymé Reaction Using Novel Functionalized Cellulose-Based Catalyst

The widespread use of petroleum-based products has raised ecological and environmental concerns, leading to increased public interest in utilizing natural resources for the development of functional materials. Cellulose, derived from various biobased sources such as plants, biomass, and bacteria, is emerging as an ideal biomaterial with significant potential for diverse applications due to its efficient, scalable, and straightforward production methods. In this study, we fabricated a novel functionalized cellulose-based catalyst by modifying Pampas Plumes (Cortaderia selloana) with (3-Mercaptopropyl)triethoxysilane (MPTS) and chlorosulfonic acid. The resulting catalyst, termed Pampas@Si/SO3H, was characterized using a range of analytical techniques, including Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), X-ray Powder Diffraction (XRD), and Brunauer − Emmett − Teller (BET) analysis.The synthesized Pampas@Si/SO3H catalyst demonstrated high efficiency as a heterogeneous catalyst in the synthesis of imidazopyridine tetracyclic derivatives via the Groebke-Blackburn-Bienaymé (GBB) reaction. This reaction involves cyclohexyl isocyanide, benzaldehyde derivatives, and various 2-aminopyridines. The advantages of this green synthesis protocol include low catalyst loading, short reaction times, stability, and recyclability for at least four reaction cycles.