Structure and NMR properties of 6-substituted-5,6-dihydrobenzo[c]phenanthridine alkaloids
| Autoři | |
|---|---|
| Rok publikování | 2013 |
| Druh | Článek v odborném periodiku |
| Časopis / Zdroj | Journal of Physical Organic Chemistry |
| Fakulta / Pracoviště MU | |
| Citace | |
| www | DOI: 10.1002/poc.3175 |
| Doi | http://dx.doi.org/10.1002/poc.3175 |
| Obor | Organická chemie |
| Klíčová slova | 1H and 13C NMR; Nucleophilic addition; X-ray diffraction; DFT calculations; Barrier to rotation; Magnetic shielding; Conformational dependence |
| Přiložené soubory | |
| Popis | We report a preparation of new 6-substituted-5,6-dihydrobenzo[c]phenanthridines by the reaction of azoles with quaternary benzo[c]phenanthridine alkaloids sanguinarine and chelerythrine. The prepared compounds have been characterized by NMR spectroscopy, mass spectrometry, and single-crystal X-ray diffraction. Conformational behaviors of carbazole derivatives in solution have been investigated by low-temperature NMR experiments. Barriers to rotation around newly formed C6–N bonds were determined to be 12–13 kcal/mol. Quantum chemical calculations have been used to reproduce the experimental observations. Large structural effects on several 1H NMR resonances were observed experimentally, analyzed by DFT calculations at B3LYP/6-311+G(d,p)/PCM level, and interpreted by ring-current effects of the benzo[c]phenanthridine and carbazole units. |
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