Nano-Fe₃O₄-Promoted Five-Component Domino Reactions for the Green Synthesis of Novel Benzo[a]phthalazino[2′,3′:1,2]pyrazolo[3,4-c]phenazines in PEG-400 as an Efficient Eco-Friendly Reaction Medium

ABSTRACT

Novel benzo[a]phthalazino[2′,3′:1,2]pyrazolo[3,4-c]phenazines containing both biologically active benzophenazine and pyrazolophthalazine templates are synthesized using a single-pot, five-component reaction involving 2-hydroxynaphthalene-1,4-dione, aromatic 1,2-diamines, hydrazine hydrate, phthalic anhydride, and benzaldehydes catalyzed by magnetic iron(III) oxide nanoparticles (Fe₃O₄ MNPs) in polyethylene glycol (PEG-400) as an inexpensive, non-toxic, and effective medium at 70°C. In this domino protocol, seven bonds (C−C, 4C−N, 2C=N) and three new rings are efficiently formed and this new green process provides the salient features such as the following: operational simplicity, high yields, low cost, reusability of Fe₃O₄ MNPs and PEG-400, absence of any tedious workup or purification, and avoidance of hazardous or toxic reagents/catalysts/solvents.

KEYWORDS:

• Benzophenazine
• green chemistry
• multi-component domino reactions (MDRs)
• PEG-400
• pyrazolophthalazine

Additional information

Funding

We gratefully acknowledge financial support from the Research Council of Young Researchers and Elite Club, Yazd Branch, Islamic Azad University, Yazd, Iran and University of Science and Arts of Yazd, Iran.