Alloglaucotoxigenin, Strukturbestimmung Glykoside und Aglykone, 280. Mitteilung

Abstract

Abstract The structure of alloglaucotoxigenin is shown to be that of 3β, 14β, 15β‐trihydroxy‐19‐oxo‐5α‐carda‐20:22‐enolide (IV) in the following way: The 19‐oxo group could be eliminated by reduction of the corresponding mercaptal. The structure of the resulting 3β, 14β, 15β‐trihydroxy‐5α‐carda‐20:22‐enolide, obtained in the acetylated form, was established through degradation and through partial synthesis by treatment of Δ 14 ‐anhydro‐uzarigenin (XIII) with osmium tetroxide. The isomeric 3β,14α, 15α‐trihydroxy‐cardenolide was also formed in large quantities. The substance XI showed in its optical rotatory dispersion curve a positive, and substance XIV a negative C OTTON effect.