Acta Cryst. (2006). E62, o919-o921  [ doi:10.1107/S1600536806003151 ]

(17S)-2,3,18,23,24-Pentahydroxy-19(1817)-abeo-28-norolean-12-en-21-one from the rhizome of Phlomis umbrosa

P. Liu, W. Qiao, W. Jia, J. Teng and H.-Q. Duan

Abstract: A new nortriterpenoid, C₂₉H₄₈O₆, with a novel skeleton was isolated from the rhizome of Phlomis umbrosa. The compound is composed of a linear array of four fused six-membered rings and a five-membered ring. The central ring has a slightly distorted half-chair conformation, while the other three six-membered rings adopt chair conformations. There are one intra- and four intermolecular hydrogen bonds, forming an extensive hydrogen-bonding network within the crystal structure.

Online 8 February 2006

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