13C nmr spectroscopy of some hetisine subtype C20-diterpenoid alkaloids and their derivatives

Abstract The 13 C NMR spectra of the diterpenoid alkaloids hetisine, hetisinone, 13-acetylhetisinone, cardiopetamine, and 15-acetylcardiopetamine, as well as certain of their derivatives, were obtained in the Fourier mode at 50.32 MHz. With the aid of proton decoupling techniques, SFORD and SFSD, and chemical shift comparisons, self-consistent assignments of nearly all the resonances have been made.