6β-Hy­droxy­eremophil-7(11)-en-8β,12-olide

Ri-Na Su; Sha Shi; Hai-Bo Wu; Wen-Shu Wang

doi:10.1107/S1600536811016308

. 2011 May 7;67(Pt 6):o1361. doi: 10.1107/S1600536811016308

6β-Hydroxyeremophil-7(11)-en-8β,12-olide

Ri-Na Su ^a, Sha Shi ^a, Hai-Bo Wu ^a, Wen-Shu Wang ^a,^*

PMCID: PMC3120521 PMID: 21754755

Abstract

The title eremophilenolide, C₁₅H₂₂O₃, is a natural compound isolated from Senecio laetus Edgew. The two cis-fused six-membered rings have chair confomations and the five-membered ring has a planar envelope conformation [maximum deviation = 0.010 (1) Å]. The β-hydroxy group participates in intermolecular O—H⋯O hydrogen bonding, forming molecular chains along the a axis.

Related literature

For related compounds extracted from Ligularia fischeri and Ligularia duciformis, see: Wang et al. (2000 ▶) and Fu et al. (2007 ▶), respectively.

Experimental

Crystal data

C₁₅H₂₂O₃
M _r = 250.33
Orthorhombic,
a = 8.0141 (16) Å
b = 9.969 (2) Å
c = 16.482 (3) Å
V = 1316.8 (5) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 293 K
0.60 × 0.60 × 0.30 mm

Data collection

Rigaku R-AXIS RAPID IP diffractometer
Absorption correction: multi-scan (ABSCOR; Higashi, 1995 ▶) T _min = 0.950, T _max = 0.975
8965 measured reflections
1744 independent reflections
1314 reflections with I > 2σ(I)
R _int = 0.061

Refinement

R[F ² > 2σ(F ²)] = 0.047
wR(F ²) = 0.107
S = 0.95
1744 reflections
168 parameters
H-atom parameters constrained
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.20 e Å⁻³

Data collection: RAPID-AUTO (Rigaku, 2000 ▶); cell refinement: RAPID-AUTO; data reduction: CrystalStructure (Rigaku/MSC, 2000 ▶); 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: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811016308/ld2005sup1.cif

e-67-o1361-sup1.cif^{(19.8KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811016308/ld2005Isup2.hkl

e-67-o1361-Isup2.hkl^{(85.9KB, 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
O3—H3⋯O1ⁱ	0.82	2.18	2.931 (2)	152

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Symmetry code: (i) Inline graphic .

Acknowledgments

The project was supported by the 985 Project (MUC985) Minzu University of China, and the Major Project for Young Teachers in Minzu University of China CUN10A, together with the "Programme of Introducing Talents of Discipline to Universities" (B08044), and the "Project for Scientific and Technical Achievements in Industrialization", Beijing Education Commission.

supplementary crystallographic information

Comment

Senecio laetus Edgew. grows in Guizhou province of China, and is traditionally used by the locals as medicine having effects on clearing fever and detoxifcation and relieving cough activities. As a part of our research on biological resources in the western area in China, the title compound, an eremophilenolide, was isolated. The compound was identified by NMR spectra, which were compared with the previous reports (Wang et al., 2000; Fu et al., 2007). Herewith, we present its crystal structure. The molecule consists of a fused three-ring system A/B/C(Fig.1). The rings A(C10–C6/C11)and B(C6–C3/C12–C11) are cis-fused; the hydroxy group at C12 site has the same β-orientation as the two methyl groups at C10 and C11. Rings A and B both are in chair conformations. The lactone ring has an envelope-like conformation with the atoms C1-C4 and O2 deviating from its mean plane by -0.002 (1), 0.008 (1), -0.010 (1), 0.007 (1) and -0.003 (1), respectively. The inter-molecular O—H···O hydrogen bonds apparently stabilize the crystal structure linking molecules into chains along [1 0 0].

Experimental

The air-dried whole plants of Senecio laetus (0.7 kg) were pulverized and triply extracted with MeOH (each time for 7 days) at room temperature. The extract was concentrated to give a residue (67 g), which was further separated by CC (SiO₂, 200–300mesh, petroleum ether/EtOAc (20:1, 15:1, 10:1, 8:1, 5:1, 3:1, 2:1, 1:1 (v/v)) to yield 8 fractions: Fr. 1–8. Each fraction was examined by TLC and combined to afford many subfractions. Fr.5a (0.5 g) was subjected to CC (SiO₂, 200–300mesh, petroleum ether/ EtOAc 10:1, 5:1 (v/v)) to provide the title compound (20 mg). ¹H and ¹³C NMR spectral data of this compound was recorded on Bruker-AV-500 s pectrometer, using CDCl₃ as solvent and Me₄Si as internal standard. The stereochemistry was established by the X-ray diffraction experiment.