Theoretical study of the structure, spectroscopic properties and anti-cancer activity of tetrahydrochromeno[4,3-b]quinolines

In the present work, a theoretical study of the geometrical structures and spectroscopic (IR, 1H and [Formula: see text]C NMR, UV-visible) properties, and anti-cancer activity of cis-fused tetrahydrochromeno[4,3-b]quinolines have been performed. The equilibrium geometries have been optimized at the B3LYP/6-31G(d) computational level and the present study puts in evidence the stability preference of the cis stereoisomers in comparison with the trans ones as expected experimentally. The vibrational frequencies and IR spectra were calculated at the same level of theory and compared to experimental FT-IR spectra and the spectral peaks have been assigned on the basis of potential energy distribution results. UV-visible absorption bands were calculated using the TD-DFT/B3LYP/6-31G(d) method. The [Formula: see text]C nuclear magnetic resonance chemical shifts and the coupling constants were calculated at the B3LYP level using the gauge independent atomic orbital (GIAO) method in chloroform solvent. The 1H chemical shifts were calculated using the recently proposed WP04/6-31G(d) DFT functional. The visualization of the molecular electrostatic potential (MEP) surfaces and the docking simulation show that the absence of the methyl group at 2-position of tetrahydrochromeno[4,3-b]quinoline moiety is responsible of the potential anti-cancer activity of this compound.