Experimental synthesis, biological evaluation, theoretical investigations of some novel benzoxazolinone based Schiff under eco-environmental conditions as potential antioxidant agents

•Lemon juice has been explored as catalyst and green solvent for the synthesis of 6-Imino 2(3H) benzoxazolinone.•Characterization of compounds by spectroscopic methods.•Antioxidant activity revealed an interesting result.•Computational modeling was performed by DFT study.•Molecular docking highlights the potential of Schiff bases as inhibitors of nitric oxide synthase NOS. In this paper, we have developed a new, non-hazardous and eco-friendly access route for the synthesis of a novel Schiff bases containing 2-oxo-3H-benzoxazole scaffold 4(a-f) by lemon juice as natural catalyzed acid under solvent-free conditions. The chemical structures of the new synthesized compounds were elucidated on the basis of the FT-IR, 1H and 13C-NMR spectroscopic techniques and all molecules were isolated with moderate yields after shorter reaction times. Furthermore, a preliminary study on the in vitro antioxidant activity of some synthesized compounds was investigated. The biological activity results revealed that highest DPPH radical-scavenging activity was observed for compound 4e with an IC50 of 2.13 µg.mL−1, more active than the standard ascorbic acid (IC50 = 2.16 µg.mL−1). In-silico studies based on density functional theory (DFT) were realized to rationalize the biological activity with the structural and electronic properties of the 6-imino-2-oxo-3H-benzoxazoles. We using the molecular docking simulation to study the affinity and the possible binding mode of complexed ligand-protein. The synthesized molecules were tested to cross the clinical test by the ADMET prediction, these results indicated that the compounds 4(a-f) have excellent drug-likeness properties. [Display omitted]