| Abstract: | The circular dichroism method has been used to establish the stereochemical features of the structure of the withasteroids.
The 22S-configuration of the asymmetric center has been confirmed for physangulide. The 22R-configuration has been confirmed
for 14α-hydroxyixocarpanolide, vamonolide, ixocarpanolide, 24,25-epoxywithanolide D, and withanolide T. On the basis of changes
in the circular dichroism spectra in acid and alkaline media it is suggested that in compounds having a 4β-hydroxy-1-oxo-5β,6β-epoxy-2,3-ene
grouping the Δ2,3 bond disappears, while in compounds having a 5α-hydroxy-1-oxo-6α,7α-epoxy-2,3-ene grouping dehydration takes place at C-4-C-5.
These characteristics can be used in the identification of the withasteroids. The isolation of withanolide T from the leaves
ofPhysalis angulata L. is described and its spectral characteristics are given.
Institute of the Chemistry of Plant Substances, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh
Soedinenii, No. 3, pp. 371–376, May–June, 1990. |
