The structure of euphorianin, an ingol diterpenoid from <i>Euphorbia poisonii</i>

The residual uncertainty in the structure of euphorianin, an ingol diterpenoid from the latex of Euphorbia poisonii, has been resolved by nuclear Overhauser enhancement difference experiments which revealed the configuration at C-19 to be S. The 1H and 13C NMR spectroscopic properties of euphorianin and its transformation products are described