<SUP>13</SUP>C Nuclear magnetic resonance spectroscopy in the elucidation of structures of diterpenoid alkaloids

<SUP>13</SUP>C Nuclear magnetic resonance spectroscopy is an exceptionally useful tool for the structure determination of diterpenoid alkaloids. A detailed study of the <SUP>1</SUP>H and <SUP>13</SUP>C 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 C<SUB>19</SUB>-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 C<SUB>19-</SUB>diterpenoid alkaloids. The structure derivation of those alkaloids was based mainly on 13C nmr spectroscopic evidence