Die Struktur der Drevogenine. 2. Mitteilung Struktur von Drevogenin P. Glykoside und Aglykone, 278. Mitteilung

Drevogenin A was converted in several steps (acetylation, hydrogenation, dehydration, hydrogenation, the haloform reaction and energetic alkaline hydrolysis) into 3β, 11α, 12β‐trihydroxy‐5α‐etianic acid, which could be characterised by its crystalline methyl ester ( 15 ) and its tri‐O‐acetyl methyl ester ( 16 ). The same acid was obtained by partial synthesis starting from hecogenin. Taking into consideration earlier results [1], the structure of drevogenin P is proved to be 3β, 11α, 12β, 14β‐tetrahydroxy‐20‐oxo‐Δ 5 ‐pregnene ( 7 ). Energetic hydrolysis of dihydro‐3‐O‐acetyldrevogenin A gave a mixture of 17αH‐ and 17βH‐desacyl‐kondurangogenin A, which were obtained in crystalline form after separation by chromatography. The only difference between the basic structures of the drevogenins and kondurangogenin A is the presence of a double bond in the 5‐position in the former.