M. Reina

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.

Chromene amides from Amyris texana

Abstract Nine new chromene amides derived from tyramine together with known chromene amides, coumarins and furoquinolines have been isolated from roots of Amyris texana . The structures of the new amides were determined by spectroscopic data and synthesized starting from tyramine. The equilibrium distribution of the syn and anti isomers of the tertiary amides was solvent-dependent. The 13 C and 1 H NMR (LIS and ASIS) data suggested that the major isomer has the NMe group syn to the carbonyl oxygen in some but anti in others, in CHCl 3 solution. However, the major isomer in all had the NMe group anti in benzene solution.

Cardionide, an Unusual C-20 Diterpenoid Alkaloid from Delphinium Cardiopetalum DC

Abstract The structure of cardionidine (1), a new hetisine-type C-20 diterpenoid alkaloid bearing an anhydride function, was inferred from spectroscopic and chemical data, and X-ray analysis.