Synthesis of 5,19-(2,6-Dimethylpyridin-4-yl)-trisnorlupane and Oleanane.

Acetylation of the 3,4-seco-derivatives of betulin, allobetulin and 28-oxyallobetulone gave the 5,19-(2,6-dimethylpyridin-4-yl)-4,23,24,20,29,30-hexanorlupane, and 5-(2,6-dimethylpyridin-4-yl)-4,23,24-trisnor-derivatives of oleanane and ursane.

Synthesis of a Novel 1,2,4-Oxadiazole Diterpene from the Oxime of the Methyl Ester of 1ß,13-Epoxydihydroquinopimaric Acid.

Oximation of the dihydroquinopimaric acid O-cyanoethylderivative (2) via the amidoxime 3, and cyclization with trifluoroacetic anhydride resulted in a new 1,2,4-oxadiazole diterpenoid (4).