Structures of shikoccin, a unique 8,9-seco-ent-kaurene diterpenoid, and shikoccidin (X-ray crystallography), a new penta-oxygenated ent-kaurene diterpenoid
Abstract
The structure of shikoccidin, a minor diterpenoid of Rabdosia shikokiana var. occidentalis, was determined by X-ray analysis to be as shown in (1), from which the structure of the main diterpenoid shikoccin was deduced to be (3).