One-pot efficient synthesis, spectroscopic characterizations and DFT calculations of new alkaloid-like polyheterocyclic annulated hydrophenanthroline skeletons

Abstract

In the current study, the hitherto unknown and complex alkaloid-like polyheterocyclic indolylhydrophenanthroline derivatives were synthesized in good yields through C-alkylation and tandem intramolecular S-alkylation of phenanthrolinium salts with indolin-2-thiones. The main features of the method, utilized for synthesis of titled compounds, were highly atom-economic reaction and the simple starting materials which could be prepared easily under mild reaction conditions. Elemental analysis, 1H and 13C NMR and FT-IR spectra were used to characterize the structure of the favored products. To compute physicochemical properties, including HOMO-LUMO analysis and 1H and 13C chemical shifts of a polycyclic indolylhydroquinoline derivative, the density functional theory (DFT) calculations were used and the results were compared with those obtained from the experimental data. The propounded mechanisms for the formation of the model structure were evaluated via the DFT calculations as well.