(3R,6R,12R,20S,24R)-20,24-Ep­oxy­dammarane-3,6,12,25-tetra­ol

Lei Zhang; Huan-Mei Guo; Wen-Juan Li; Yi-Jun Gao; Qing-Guo Meng

doi:10.1107/S1600536811008609

. 2011 Mar 12;67(Pt 4):o846. doi: 10.1107/S1600536811008609

(3R,6R,12R,20S,24R)-20,24-Epoxydammarane-3,6,12,25-tetraol

Lei Zhang ^a, Huan-Mei Guo ^b, Wen-Juan Li ^a, Yi-Jun Gao ^a, Qing-Guo Meng ^a,^*

PMCID: PMC3099824 PMID: 21754128

Abstract

In the title compound, C₃₀H₅₂O₅, the 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 sofa. Intramolecular O—H⋯O hydrogen bonds may influence the conformation of the molecule. In the crystal, molecules are linked by intermolecular O—H⋯O hydrogen bonds, forming a three-dimensional network.

Related literature

The title compound was prepared from 20(S)-protopanaxatriol which was degraded from Panax quinquefolium saponin. For background to and the medicinal properties of Panax ginseng and Panax quinquefolium, see: Shibata et al. (1985 ▶); Takano et al. (1999 ▶); Yu et al. (2007 ▶); Wang et al. (2010 ▶). For related structures, see: Shi et al. (1992 ▶); Meng et al. (2010 ▶).

Experimental

Crystal data

C₃₀H₅₂O₅
M _r = 492.72
Orthorhombic,
a = 12.7918 (6) Å
b = 13.7842 (7) Å
c = 16.0902 (8) Å
V = 2837.1 (2) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 298 K
0.54 × 0.50 × 0.50 mm

Data collection

Bruker SMART CCD diffractometer
16320 measured reflections
3141 independent reflections
2911 reflections with I > 2σ(I)
R _int = 0.020

Refinement

R[F ² > 2σ(F ²)] = 0.042
wR(F ²) = 0.113
S = 1.05
3141 reflections
325 parameters
6 restraints
H-atom parameters constrained
Δρ_max = 0.26 e Å⁻³
Δρ_min = −0.24 e Å⁻³

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 Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811008609/lh5198sup1.cif

e-67-0o846-sup1.cif^{(29.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811008609/lh5198Isup2.hkl

e-67-0o846-Isup2.hkl^{(154.1KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1A⋯O2	0.82	2.41	2.882 (3)	117
O2—H2⋯O5	0.82	1.95	2.697 (2)	152
O3—H3⋯O4ⁱ	0.82	2.12	2.929 (3)	169
O4—H4⋯O2ⁱⁱ	0.82	2.13	2.890 (2)	153

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

The authors thank Mr Lian-Dong Liu (College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan 250014, People’s Republic of China) for his invaluable support of the X-ray data collection. The authors would like to thank Shandong Provincial Natural Science Foundation, China (Y2007C138,Y2008B29), the Scientific Reasearch Foundation of the Higher Education Institutions of Shandong Province, China (J07WE26), the National Natural Science Foundation of China (No.81001358) and the Promotive Research Fund for Excellent Young and Middle-aged sScientisits of Shandong Province (No. BS2010YY073) for research grants.

supplementary crystallographic information

Comment

Both Panax ginseng and Panax quinquefolium, belonging to Araliaceae, are well known traditional medicinal herbs. They are used as tonics and for the treatment for diseases, such as tumor and myocardial ischemia. Panax ginseng contains numbers of saponins, namely ginsenoside and an oleanolic acid-type saponin in addition to the major protopanaxadiol and protopanaxatriol-type saponins (Shibata et al.,1985). Panax quinquefolium contains an ocotillol-type (20S, 24R-epoxyside) saponin with high anti-tumor activity (Takano et al.,1999), as well as oleanolic acid-type, protopanaxadiol and protopanaxatriol-type saponins. (3R,6R,12R,20S,24S)-20,24-Epoxy-dammarane-3,6,12,25-tetraol and (3R,12R,20S,24R)-20,24-epoxy-dammarane-3,12,25-triol are found to possess cardioprotective effect on myocardial injury induced by isoproterenol in rats (Yu et al.,2007; Wang et al., 2010). As part of our ongoing investigation of ocotillol-type compounds and their cardioprotective effect on myocardial injury, we report herein the crystal structure of the title compound, (I).

The molecular structure of (I) is shown in Fig. 1. In the molecule, all bond lengths and angles are within normal ranges (Shi et al.,1992; Meng et al., 2010). The six-membered rings A(C11,C13,C16,C17,C18,C19), B(C13,C15,C16,C22,C32,C33), and C(C22,C24,C25,C26,C29,C32) are in chair conformations. Ring D(C8,C9,C10,C11,C19) has an envelope form with atom C11 forming the flap. The tetrahydrofuran ring has a conformation intermediate between half-chair and sofa forms. In the crystal, molecules are linked by O—H···O hydrogen bonds (Table 1) to form a three-dimensional network.

Experimental

20(S)-protopanaxatriol was degraded from Panax quinquefolium saponin with sodium in glycerine at about 473 - 503K and seperated by silica flash chromatography. (3R,6R,12R,20S,24R)-20,24-Epoxy-dammarane-3,6,12,25-tetraol was synthesized from 20(S)-protopanaxatriol in the presence of N,N-dimethylaminopyridine, pyridine and acetic anhydride. The esters were oxidized by m-CPBA and the title compound was obtained by saponification with sodium hydroxide in DMSO and seperated by silica flash chromatography. Finally, the crystals were dried at room temperature the title compound was crystallized from ethyl acetate. Single crystals suitable for X-ray measurements were obtained by recrystallization of an acetone solution of the title compound at room temperature.