Quantum computational, spectroscopic and molecular docking studies of potent tuberculosis drug 2,6-dihydroxypyridine-4-carboxylic acid and 2‑hydroxy -6-methylpyridine-4-carboxylic acid

Abstract

This study reports the molecular structure and spectroscopic (FT-IR, FT-Raman, UV–Vis, 1H and 13C NMR) investigations of 2,6-dihydroxypyridine-4-carboxylic acid (HPC) (citrazinic acid) and 2‑hydroxy -6-methylpyridine-4-carboxylic acid (HMPC) molecules. The quantum computational calculations were performed by density functional theory (DFT) method using the B3LYP/ 6–311++G (d,p) basis set. The vibrational wavenumbers and NMR chemical shifts were matched well with the experimental data. The title molecules exhibited two kinds of dimers such as J and H- type dimers. The Mulliken atomic charge distribution for neutral, anionic, and cationic states was performed to predict Fukui function and global softness of the molecules. From the molecular electrostatic potential (MEP) map the reactive sites were identified and the reactivity of the title compounds was examined through the HOMO-LUMO energy gap. Natural Bonding Orbital (NBO) analysis revealed that the presence of stabilization interactions within the title molecules. In addition, the molecular docking studies carried out for title molecules to determine protein ligand interaction to confirm the inhibition activity against Mycobacterium tuberculosis. Additionally, the non-linear optical property was also calculated for title molecules.