[Coetsoidin A, a new diterpenoid from Rabdosia coetsoides C. Y. Wu]

From the leaves of Rabdosia coetsoides C. Y. Wu, a new diterpenoid, coetsoidin A (I) was isolated and its structure was established by spectroscopic and X-ray diffraction analysis. It is the first instance of a kaurene type diterpenoid possessing alpha,beta-unsaturated ketone functionality in ring B.