Green synthesis and biological activities assessment of some new chromeno[2,3-b]pyridine derivatives.

Magnetite nanoparticles (MNPs) composed of γ-FeO and hydroxyapatite (HAp) were modified by hexamethylen-1,6-diisocyanate (HMDI) followed by thiourea dioxide and used as recyclable catalyst for the synthesis of some newly derivatives of chromeno[2,3-b]pyridine. The products were synthesized in excellent yields via one-pot three-component reactions of 3-cyano-6-hydroxy-4-methyl-pyridin-2(1H)-one with aldehydes and dimedone under solvent-free conditions. The successful synthesis of products were confirmed using Fourier transform infrared (FTIR), proton/carbon nuclear magnetic resonance (H/C NMR), and mass spectroscopies as well as physical data (e.g., melting points and elemental composition). The in vitro antioxidant and antifungal activities of the synthesized samples were evaluated using scavenging effects on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and potato dextrose agar (PDA) medium, respectively. Based on results, the chromeno[2,3-b]pyridine derivatives exhibited excellent biological activities that qualified them for biomedical applications.