13C nuclear magnetic resonance spectra of amaryllidaceae alkaloids. I—alkaloids with the crinane skeleton



The13C NMR spectra of 15 Amaryllidaceae alkaloids with the crinane skeleton were measured and the chemical shifts unequivocally assigned. From the derived specific shift ranges, it is possible to establish both the complete oxygenation pattern of the 5, 10b-ethanophenanthridine skeleton and its stereochemical arrangement.