Green one-pot synthesis of quinoxaline derivatives using sulfo-anthranilic acid functionalized alginate-MCFe₂O₄ nanostructures: a novel superparamagnetic catalyst with antiproliferative potential

This study reports a green, multi-component synthesis of 2-aminoimidazole-linked quinoxaline Schiff bases using a novel superparamagnetic acid catalyst. The catalyst consists of sulfo-anthranilic acid (SAA) immobilized on MnCoFe₂O₄@alginate magnetic nanorods (MNRs), achieving high SAA loading (1.8 mmol g^-1) and product yields (91-97%). Characterization of the MCFe₂O₄@Alginate@SAA MNR catalyst revealed an inverse spinel structure (XRD), a saturation magnetization of 31 emu g^-1 (VSM), 17.5% organic content (TGA), and a rod-like morphology with diameters of 30-60 nm and lengths of 150-250 nm (SEM). Elemental composition confirmed by EDX analysis indicated successful SAA immobilization and high catalyst purity. The synthesized quinoxaline derivatives were evaluated for antiproliferative activity against SKOV3 and HCT-116 cancer cell lines using the MTT assay. Several compounds, notably 4a, 4s, 4t, 4w, and 4x, exhibited potent activity, inhibiting HCT-116 proliferation by >50% at 50 μg mL^-1. Compound 4a demonstrated the most significant inhibition, with 82.3% against SKOV3 cells after 48 h and 69.0% against HCT-116 cells after 24 h, both at 50 μg mL^-1. These results suggest the potential of 2-aminoimidazole-linked quinoxaline Schiff bases, particularly 4a, as promising multi-target chemotherapy agents.