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

ABSTRACTNovel 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.