Received 18 November 2010
The title compound, C36H58O8, was prepared from 20(S)-protopanaxatriol, which was degraded from Panax quinquefolium saponin with sodium in glycerine, extracted and seperated by flash chromatography. Three six-membered rings are in chair conformations, the five-membered ring is in an envelope form and the tetrahydrofuran ring has a conformation intermediate between half-chair and envelope. In the crystal, molecules are linked by O-HO hydrogen bonds, and C-HO contacts also occur. The absolute structure was assigned on the basis of the synthesis.
For background to the medicinal uses of Araliaceae-type natural products, see: Shibata et al. (1985); Takano et al. (1999); Yu et al. (2007); Wang et al. (2010). For related structures, see: Iljin et al. (1982); Shi et al. (1992).
Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: HB5749 ).
The authors thank Mr. Lian-dong Liu (College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University) for his invaluable support with the X-ray data collection. The authors would like to thank Shandong Provincial Natural Science Foundation, China (Y2007C138), and the Scientific Reasearch Foundation of the Higher Education Institutions of Shandong Province and China (J07WE26) for a research grant.
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