Studies on the Diterpenoids of Rabdosia longituba (MIQ.) HARA : Structure of a New Bitter Diterpenoid, Rabdolongin A, and the Absolute Stereochemistry of Rabdolongin B (=Maoecrystal D)

Abstract

From the dried aerial parts of Rabdosia longituba (MIQ) HARA, a new bitter diterpenoid, rabdolongin A (1), was isolated and its structure was elucidated on the basis of spectroscopic and chemical evidence. The absolute stereochemistry of rabdolongin B (=maoecrystal D) (6) was chemically established by correlation with trichokaurin (8) possessing known absolute stereochemistry.