13C Nuclear magnetic resonance spectroscopy in the elucidation of structures of diterpenoid alkaloids

Abstract

13C Nuclear magnetic resonance spectroscopy is an exceptionally useful tool for the structure determination of diterpenoid alkaloids. A detailed study of the 1H and 13C nmr spectra of aconitine and 3-deoxyaconitine has permitted definite assignments to all the carbon atoms of the molecule. Chemical shift revisions have been suggested for certain carbon atoms of the C19-diterpenoid alkaloids. Chemical examination of Aconitumcolumbianum Nutt. ssp. columbianum, A. forrestii Stapf, Delphiniumtatsienense Franch., and D. vestitum Wall, resulted in the isolation of several new C19-diterpenoid alkaloids. The structure derivation of those alkaloids was based mainly on 13C nmr spectroscopic evidence.