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‐Δ5‐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.