CS-[BiC-PiC]-NiCl 4 : a green and effective heterogeneous catalyst for one-pot synthesis of 2,3-dihydroquinazolin-4(1 H )-one derivatives

)-one derivatives using two distinct protocols, including the reaction of 2-aminobenzamide with aldehydes and the reaction of isatoic anhydride with ammonium acetate and aldehydes under neat conditions at 120 °C, demonstrating excellent recyclability over five runs, achieving high yields (93-97%) with short reaction times (3-8 minutes). This offers a sustainable and practical synthetic platform, facilitated by the synergistic interplay between the nickel Lewis acid sites and the chitosan support. This process provides significant advantages, including operational simplicity, solvent-free conditions, straightforward product isolation, and easy recovery of a cost-effective catalyst, which demonstrated exceptional stability over multiple cycles with no detectable nickel leaching, underscoring its truly heterogeneous nature. Consequently, this methodology represents a sustainable and practical approach for the synthesis of these valuable heterocycles.