6,8-Dihy­droxy-8a-methyl-3,5-dimethyl­idenedeca­hydro­naphtho­[2,3-b]furan-2(3H)-one

Ting-ting Liu; Hai-Bo Wu; Wen-Shu Wang

doi:10.1107/S160053681204425X

. 2012 Oct 31;68(Pt 11):o3251. doi: 10.1107/S160053681204425X

6,8-Dihydroxy-8a-methyl-3,5-dimethylidenedecahydronaphtho[2,3-b]furan-2(3H)-one

Ting-ting Liu ^a, Hai-Bo Wu ^a, Wen-Shu Wang ^a,^*

PMCID: PMC3515328 PMID: 23284548

Abstract

The title compound, C₁₅H₂₀O₄, is a eudesmanolide isolated from the Chinese medicinal plant Carpesium triste Maxim. The molecule contains three rings, viz. two fused six-membered rings in chair conformations and a five-membered ring in a flattened envelope conformation. In the crystal, two hydroxy groups are involved in the formation of intra- and intermolecular O—H⋯O hydrogen bonds. The H atoms in these groups are split, with site-occupation factors of 0.5. The intermolecular hydrogen bonds link molecules into chains propagating in [010].

Related literature

For related compounds extracted from Carpesium triste Maxim, see: Masao & Fumiko (1975 ▶).

Experimental

Crystal data

C₁₅H₂₀O₄
M _r = 264.31
Tetragonal,
a = 6.4737 (4) Å
c = 62.438 (8) Å
V = 2616.7 (5) Å³
Z = 8
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 133 K
0.54 × 0.48 × 0.32 mm

Data collection

Rigaku AFC10/Saturn-724+ CCD diffractometer
19607 measured reflections
1990 independent reflections
1826 reflections with I > 2σ(I)
R _int = 0.058

Refinement

R[F ² > 2σ(F ²)] = 0.047
wR(F ²) = 0.124
S = 1.00
1990 reflections
185 parameters
6 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.23 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Data collection: CrystalClear (Rigaku/MSC, 2008 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; 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

Click here for additional data file.^{(20KB, cif)}

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S160053681204425X/rk2376sup1.cif

e-68-o3251-sup1.cif^{(20KB, cif)}

Click here for additional data file.^{(98KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S160053681204425X/rk2376Isup2.hkl

e-68-o3251-Isup2.hkl^{(98KB, hkl)}

Click here for additional data file.^{(5.8KB, cml)}

Supplementary material file. DOI: 10.1107/S160053681204425X/rk2376Isup3.cml

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
O2—H2O⋯O2ⁱ	0.84 (1)	1.90 (1)	2.733 (3)	173 (5)
O2—H2O′⋯O3	0.84 (1)	1.94 (2)	2.690 (2)	148 (2)
O3—H3O′⋯O2	0.84 (1)	1.97 (4)	2.690 (2)	143 (5)
O3—H3O⋯O3ⁱⁱ	0.83 (1)	1.88 (2)	2.697 (3)	168 (6)

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

Acknowledgments

The project was supported by the 985 Project (grant Nos. MUC98504-14, MUC98507-08), Minzu University of China, together with the ‘Programme of Introducing Talents of Discipline to Universities’ (grant No. B08044), and the ‘Project for Scientific and Technical Achievements in Industrialization’, Beijing Education Commission.

supplementary crystallographic information

Comment

Carpesium triste Maxim grows in the northeast and southwest area of mainland China. It is used as traditional Chinese medicine having effects on detoxification and antibacterial activities. As a part of our research on biological resource by ethnic minorities in Guizhou province, the title compound was isolated form Carpesium triste Maxim. Its structure was identified by NMR spectra data and compared with the previous reports (Masao & Fumiko, 1975). Herewith we present its molecular structure. The molecule of the title compound contains a three-ring system A/B/C (Fig. 1). Ring A and B are both in chair conformations and there is a trans-junction between ring A (C1-C5/C10) and ring B (C5-C7/C8-C10). Furthermore, the methyl group at C14 sites is in the opposite orientation with the two hydroxyl groups at C1 and C3 sites. The furan ring C (C8-C12/O1) is in an envelope-like conformation. Two hydroxy groups contribute to the formation of intra- and inter-molecular O–H···O hydrogen bonds (Table 1). The latter ones link molecules into chain propagated in direction [0 1 0].

Experimental

The air-dried whole plant of Carpesium triste Maxim (0.337 kg) were pulverized and extracted three times with CH₃OH (each for less than 1 minutes) at room temperature by flash-type extractor. The extract was concentrated to give a residue (33.5 g), which was further separated by CC (SiO₂, 200-300 mesh, petroleum ether/acetone (25:1, 20:1, 15:1, 10:1, 8:1, 5:1, 3:1, 2:1, 1:1(v/v)) to yield 9 fractions: Fr. 1-9. Each fraction was examined by TLC and combined to afford many subfractions. Fr. 5 (270 mg) was subjected to Sephadex LH-20 (CHCl₃/CH₃OH 1:1) to provide the title compound (4 mg). ¹H and ¹³C NMR spectral data of this compound was recorded on Bruker-AV-500 spectrometer, using CDCl₃ as solvent and Me₄Si as internal standard. The relative stereochemistry can be observed by X-ray diffraction experiment.