Synthesis and Characterization of Benzene fused N-heterocycles and its Derivatives Using CuO Nanoparticles as a Heterogeneous Catalyst

The development of efficient and environmentally sustainable synthetic methods for biologically active heterocycles remains a major goal in modern organic chemistry. In the present work, a small library of benzene-fused N-heterocycles, including benzimidazole, benzoxazole, and benzothiazole derivatives, was synthesized using copper oxide nanoparticles (CuO NPs) as a recyclable and eco-friendly heterogeneous catalyst. The target compounds were prepared through a one-pot condensation–cyclization–oxidation protocol under mild reaction conditions, affording good to excellent yields. The catalytic system demonstrated high efficiency, operational simplicity, and easy recovery, making it suitable for green chemistry applications. All synthesized derivatives were structurally characterized using 1H NMR, 13C NMR, and mass spectrometry. The results highlight the potential of CuO nanoparticles as an effective heterogeneous catalyst for the rapid synthesis of benzene-fused heterocycles. Furthermore, the obtained compounds represent promising scaffolds for future development of targeted anticancer and pharmacologically active agents.