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In the present work, 2-substituted benzoxazole derivatives were synthesized from 2-(benzo[d]oxazol-2-yl) aniline. All the synthesized compounds were purified and characterized by 1H NMR, 13C NMR, and mass spectroscopy. All the compounds were pharmacologically evaluated for its in vitro anti-inflammatory efficacy using membrane stabilization and proteinase inhibitory methods. In addition to this, in silico molecular docking studies were carried out to predict the binding affinity of the synthesized benzoxazole derivatives with prostaglandin H2 synthase (PGHS) protein and trypsin enzyme. The results obtained from in vitro anti-inflammatory studies showed that compound 3, 4, and 6a showed good efficacy with percentage inhibition of 74.26 ± 1.04, 80.16 ± 0.24, and 70.24 ± 0.68 for membrane stabilization activity 80.19 ± 0.05, 85.30 ± 1.04, and 75.68 ± 1.28 towards proteinase inhibitory efficacy at a concentration of 100 μg/mL which was on par to that of standards aceclofenac and etodolac. Molecular docking analysis showed that compounds 3 and 4 possess good binding affinity towards PGHS protein with a docking score of − 9.4 and − 9.3 kcal/mol respectively.

The structural and spectroscopic characteristics of the synthesized structurally novel compound 4-chloro-6-methylquinoline-2(1H)-one (4C6MQ) and its isomer 4-chloro-8-methylquinoline-2(1H)-one (4C8MQ) have been examined by means of experimental and computational quantum chemical methods like density functional theory (DFT). The crystal structure of the 4C6MQ compound has been brought to light by single-crystal x-ray diffraction (SCXRD) method which consists of two independent molecules (A and B) in the asymmetric unit with similar conformations. Both the isomer compounds are characterized spectroscopically by FTIR, FT-Raman, UV-Vis, and NMR spectrum and compared with DFT results. The geometries of the isomer compounds have been optimized by using DFT/B3LYP method with the 6-311G++(d,p) basis sets. From the optimized geometry of the compounds, geometric parameters (bond lengths, bond angles, and torsion angles); vibrational analysis; chemical shifts; and electronic absorption of the isomer compounds have been computed and compared with the experimental result. The detailed assignments of vibrational wave numbers have been prepared based on potential energy distribution (PED) which was carried out in the VEDA4 program. In addition, natural bonding orbital analysis, frontier molecular orbital, and molecular electrostatic potential have been explained theoretically. The in silico (absorption, distribution, metabolism, excretion and toxicity) studies were analyzed to identify the potential drug likeliness of the isomer compounds. The implications of the inhibitory activity of isomer compounds against DNA gyrase and lanosterol 14 α-demethylase enzyme by molecular docking are discussed. Further, the isomer compounds were screened for their antibacterial and antifungal activities.