A Highly Efficient and Green Synthesis of Pyrimido-Fused Benzophenazines via Microwave-Assisted and H₃PW₁₂O₄₀@Nano-ZnO Catalyzed a Sequential One-Pot Cyclization in Aqueous Medium

Abstract

A rapid, efficient, and environmentally benign procedure for the synthesis of novel heteroaryl-substititued dihydrobenzo[a]pyrimido[5′,4′:5,6]pyrido[2,3-c]phenazines has been developed via condensation/Knoevenagel/Michael/heterocyclization reactions of 2-hydroxynaphthalene-1,4-dione, o-phenylenediamine, aromatic aldehydes, and 6-amino-1,3-dimethyluracil in the presence of H₃PW₁₂O₄₀@nano-ZnO as a recyclable heterogeneous catalyst in aqueous medium under microwave irradiation. This sequential green process with main aspects such as: operational simplicity, high yields, low cost, easy handling, eco-friendly and reusability of the catalyst, absence of any tedious workup, or purification and avoidance of hazardous or toxic reagents/catalysts/solvents opens an effective and convenient way to pyrimido-functionalized benzophenazine systems, which are promising compounds for different biomedical applications.

Keywords:

• 1,4-dihydropyridine
• Benzophenazine
• environmentally friendly
• H₃PW₁₂O₄₀@nano-ZnO
• microwave irradiation
• multicomponent reactions

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Research Council of Islamic Azad University of Yazd.