organic compounds
8β-Ethoxyeremophil-3,7(11)-diene-8α,12;6α,15-diolide
aSchool of Pharmacy, Lanzhou University, Lanzhou 730000, People's Republic of China
*Correspondence e-mail: feidq@lzu.edu.cn
The title compound, C17H20O5, an eremophilane sesquiternoid, was isolated from the roots of Ligularia lapathifolia. The molecule contains four fused rings of which the six-membered ring A adopts a half-chair conformation, the six-membered ring B adopts a chair conformation, the five-membered ring C is almost planar (r.m.s. deviation = 0.015 Å) and the five-membered ring D adopts an with the quaternary C atom as the flap. The methyl and the ethoxy groups adopt a syn conformation and the A/B ring junction is cis-fused. No directional intermolecular interactions could be identified in the crystal.
Related literature
For further information on the isolation of the title compound, see Fei et al. (2007). For pucking paramaters, see: Cremer & Pople (1975); Boeyens (1978)
Experimental
Crystal data
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Data collection: CrysAlis PRO (Agilent, 2013); cell CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SUPERFLIP (Palatinus & Chapuis, 2007); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2.
Supporting information
The air-dried roots of L. lapathifolia (3.6 kg) were powdered and extracted with petroleum ether -diethyl ether-acetone (1:1:1) three times successively at room temperature. The combined extracts were concentrated in vacuum to obtain a residue (270 g), which was subjected to silica gel CC and eluted with petroleum ether-acetone (50:1, 20:1, 8:1, 5:1, 2:1, 1:1, 0:1). On the basis of differences in composition indicated by TLC, seven crude fractions (A—G) were obtained. Fraction B was further fractionated on a silica gel column using petroleum ether-acetone (30:1, 10:1, 5:1, 2:1) to give four crude fractions (B1—B4). Fraction B3 was further fractionated on a silica gel column using petroleum ether-acetone (20:1, 8:1, 2:1) to obtain the pure title compound. Colourless blocks were obtained by slow evaporation of a methanol solution at room terperature.
All H atoms attached to C atoms were fixed geometrically and treated as riding with C—H = 0.96 Å (methyl), 0.97 Å (methylene), 0.98 Å (methine) and 0.93 Å (C=CH) with Uiso(H) = 1.2Uep(C) or Uiso(H) = 1.5Ueq(Cmethyl). The
tentatively indicates the absolute structure.The title compound, 8β-ethoxyeremophil-3,7(11)-diene-8α,12(6α,15)-diolide (Fig. 1), was isolated from the roots of Ligularia lapathifolia (Fei et al., 2007). The title compound is composed of four rings, two six-membered and two five-menbered. The six-membered ring A adopt a half-chair conformation, which has pucking paramaters (Cremer & Pople, 1975; Boeyens, 1978) Q = 0.4766 (19) Å, θ = 130.0 (2)°, φ = 133.8 (3)°. The six-membered ring B adopt a chair conformation with pucking paramaters Q = 0.5073 (17) Å, θ = 22.08 (19)°, φ = 205.7 (5)°. The five-membered ring C is almost planar with a mean torsion angle of 1.50 (8)°. The five-membered ring D adopt an The A/B ring junction is -fused (torsion angle C14—C5—C10—H10 = 43°).
For further information on the isolation of the title compound, see Fei et al. (2007). For pucking paramaters, see: Cremer & Pople (1975); Boeyens (1978)
Data collection: CrysAlis PRO (Agilent, 2013); cell
CrysAlis PRO (Agilent, 2013); data reduction: CrysAlis PRO (Agilent, 2013); program(s) used to solve structure: SUPERFLIP (Palatinus & Chapuis, 2007); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).Fig. 1. The molecular structure of the title compound, showing displacement ellipsoids at the 30% probability level. |
C17H20O5 | Dx = 1.292 Mg m−3 |
Mr = 304.33 | Cu Kα radiation, λ = 1.5418 Å |
Orthorhombic, P212121 | Cell parameters from 9242 reflections |
a = 8.4925 (2) Å | θ = 4.6–70.7° |
b = 13.0302 (4) Å | µ = 0.78 mm−1 |
c = 14.1381 (9) Å | T = 294 K |
V = 1564.50 (12) Å3 | Block, colourless |
Z = 4 | 0.33 × 0.28 × 0.12 mm |
F(000) = 648 |
Agilent SuperNova (Dual, Cu at zero, Eos) diffractometer | 2994 independent reflections |
Radiation source: SuperNova (Cu) X-ray Source | 2871 reflections with I > 2σ(I) |
Mirror monochromator | Rint = 0.027 |
Detector resolution: 16.0733 pixels mm-1 | θmax = 70.8°, θmin = 4.6° |
ω scans | h = −10→9 |
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2013) | k = −15→15 |
Tmin = 0.743, Tmax = 1.000 | l = −16→17 |
14336 measured reflections |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.037 | H-atom parameters constrained |
wR(F2) = 0.103 | w = 1/[σ2(Fo2) + (0.0636P)2 + 0.1574P] where P = (Fo2 + 2Fc2)/3 |
S = 1.03 | (Δ/σ)max = 0.003 |
2994 reflections | Δρmax = 0.13 e Å−3 |
202 parameters | Δρmin = −0.18 e Å−3 |
0 restraints | Absolute structure: Flack (1983), 000 Friedel pairs |
Primary atom site location: iterative | Absolute structure parameter: −0.1 (2) |
C17H20O5 | V = 1564.50 (12) Å3 |
Mr = 304.33 | Z = 4 |
Orthorhombic, P212121 | Cu Kα radiation |
a = 8.4925 (2) Å | µ = 0.78 mm−1 |
b = 13.0302 (4) Å | T = 294 K |
c = 14.1381 (9) Å | 0.33 × 0.28 × 0.12 mm |
Agilent SuperNova (Dual, Cu at zero, Eos) diffractometer | 2994 independent reflections |
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2013) | 2871 reflections with I > 2σ(I) |
Tmin = 0.743, Tmax = 1.000 | Rint = 0.027 |
14336 measured reflections |
R[F2 > 2σ(F2)] = 0.037 | H-atom parameters constrained |
wR(F2) = 0.103 | Δρmax = 0.13 e Å−3 |
S = 1.03 | Δρmin = −0.18 e Å−3 |
2994 reflections | Absolute structure: Flack (1983), 000 Friedel pairs |
202 parameters | Absolute structure parameter: −0.1 (2) |
0 restraints |
Experimental. CrysAlisPro, Agilent Technologies, Version 1.171.36.28 (release 01-02-2013 CrysAlis171 .NET) (compiled Feb 1 2013,16:14:44) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm. |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
O1 | 0.9183 (2) | 0.64050 (12) | 0.11330 (10) | 0.0794 (4) | |
O2 | 0.79269 (15) | 0.60175 (8) | 0.24732 (9) | 0.0556 (3) | |
O3 | 0.82873 (14) | 0.24550 (10) | 0.20230 (9) | 0.0580 (3) | |
O4 | 0.6780 (2) | 0.17448 (13) | 0.09057 (11) | 0.0839 (5) | |
O5 | 0.81102 (14) | 0.52062 (10) | 0.39285 (7) | 0.0514 (3) | |
C1 | 0.3694 (2) | 0.36787 (16) | 0.35509 (16) | 0.0642 (5) | |
H1A | 0.3487 | 0.3085 | 0.3945 | 0.077* | |
H1B | 0.3133 | 0.4257 | 0.3822 | 0.077* | |
C2 | 0.3051 (2) | 0.34733 (16) | 0.25617 (17) | 0.0678 (5) | |
H2A | 0.2071 | 0.3096 | 0.2617 | 0.081* | |
H2B | 0.2818 | 0.4124 | 0.2260 | 0.081* | |
C3 | 0.4146 (2) | 0.28847 (14) | 0.19487 (14) | 0.0582 (4) | |
H3 | 0.3795 | 0.2650 | 0.1365 | 0.070* | |
C4 | 0.5619 (2) | 0.26851 (12) | 0.22151 (12) | 0.0484 (4) | |
C5 | 0.63488 (19) | 0.29910 (12) | 0.31377 (12) | 0.0467 (4) | |
C6 | 0.80727 (18) | 0.31837 (12) | 0.27873 (11) | 0.0457 (4) | |
H6 | 0.8817 | 0.3034 | 0.3299 | 0.055* | |
C7 | 0.83272 (17) | 0.42502 (11) | 0.24365 (11) | 0.0416 (3) | |
C8 | 0.75684 (19) | 0.50977 (12) | 0.30066 (11) | 0.0436 (3) | |
C9 | 0.58186 (19) | 0.49238 (12) | 0.30652 (12) | 0.0460 (4) | |
H9A | 0.5376 | 0.4907 | 0.2433 | 0.055* | |
H9B | 0.5331 | 0.5486 | 0.3407 | 0.055* | |
C10 | 0.5468 (2) | 0.39090 (12) | 0.35713 (12) | 0.0481 (4) | |
H10 | 0.5794 | 0.3977 | 0.4233 | 0.058* | |
C11 | 0.89795 (19) | 0.46356 (14) | 0.16573 (11) | 0.0485 (4) | |
C12 | 0.8750 (2) | 0.57663 (15) | 0.16860 (12) | 0.0551 (4) | |
C13 | 0.9784 (2) | 0.4157 (2) | 0.08268 (13) | 0.0680 (5) | |
H13A | 1.0069 | 0.3463 | 0.0978 | 0.102* | |
H13B | 1.0715 | 0.4541 | 0.0676 | 0.102* | |
H13C | 0.9085 | 0.4159 | 0.0293 | 0.102* | |
C14 | 0.6368 (3) | 0.20772 (17) | 0.38296 (16) | 0.0726 (6) | |
H14A | 0.6874 | 0.2279 | 0.4408 | 0.109* | |
H14B | 0.6935 | 0.1516 | 0.3551 | 0.109* | |
H14C | 0.5307 | 0.1867 | 0.3961 | 0.109* | |
C15 | 0.6863 (2) | 0.22373 (14) | 0.16241 (14) | 0.0575 (4) | |
C16 | 0.9771 (2) | 0.5300 (2) | 0.40545 (14) | 0.0762 (7) | |
H16A | 1.0163 | 0.5873 | 0.3686 | 0.091* | |
H16B | 1.0290 | 0.4681 | 0.3835 | 0.091* | |
C17 | 1.0122 (3) | 0.5461 (3) | 0.50483 (17) | 0.0970 (9) | |
H17A | 1.1237 | 0.5406 | 0.5148 | 0.146* | |
H17B | 0.9588 | 0.4953 | 0.5420 | 0.146* | |
H17C | 0.9773 | 0.6133 | 0.5234 | 0.146* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0966 (11) | 0.0798 (10) | 0.0619 (8) | −0.0179 (9) | 0.0110 (8) | 0.0133 (8) |
O2 | 0.0652 (7) | 0.0444 (6) | 0.0572 (7) | −0.0037 (5) | 0.0106 (6) | −0.0012 (5) |
O3 | 0.0483 (6) | 0.0539 (6) | 0.0718 (7) | 0.0118 (5) | −0.0004 (6) | −0.0224 (6) |
O4 | 0.0807 (10) | 0.0882 (11) | 0.0828 (10) | −0.0103 (9) | 0.0044 (8) | −0.0454 (9) |
O5 | 0.0490 (6) | 0.0629 (7) | 0.0422 (6) | −0.0064 (5) | 0.0061 (5) | −0.0128 (5) |
C1 | 0.0469 (9) | 0.0657 (12) | 0.0800 (13) | −0.0003 (9) | 0.0186 (9) | 0.0034 (10) |
C2 | 0.0406 (8) | 0.0616 (10) | 0.1014 (15) | −0.0028 (8) | 0.0023 (10) | 0.0036 (11) |
C3 | 0.0480 (9) | 0.0559 (9) | 0.0707 (11) | −0.0084 (7) | −0.0062 (8) | −0.0015 (9) |
C4 | 0.0457 (8) | 0.0414 (8) | 0.0580 (9) | −0.0049 (6) | −0.0002 (7) | −0.0044 (7) |
C5 | 0.0457 (8) | 0.0435 (8) | 0.0510 (9) | 0.0038 (6) | 0.0009 (7) | 0.0012 (7) |
C6 | 0.0404 (7) | 0.0469 (8) | 0.0497 (8) | 0.0094 (6) | −0.0042 (7) | −0.0087 (7) |
C7 | 0.0349 (7) | 0.0486 (8) | 0.0412 (7) | 0.0026 (6) | −0.0023 (6) | −0.0095 (6) |
C8 | 0.0452 (8) | 0.0428 (8) | 0.0427 (8) | −0.0009 (6) | 0.0051 (6) | −0.0042 (6) |
C9 | 0.0431 (8) | 0.0442 (8) | 0.0508 (8) | 0.0066 (6) | 0.0069 (7) | −0.0044 (7) |
C10 | 0.0462 (8) | 0.0507 (9) | 0.0474 (8) | 0.0020 (7) | 0.0096 (7) | −0.0004 (7) |
C11 | 0.0405 (8) | 0.0662 (10) | 0.0387 (8) | 0.0000 (7) | 0.0016 (6) | −0.0077 (7) |
C12 | 0.0544 (10) | 0.0647 (10) | 0.0462 (9) | −0.0088 (8) | 0.0015 (7) | 0.0037 (8) |
C13 | 0.0609 (11) | 0.0976 (15) | 0.0454 (9) | 0.0077 (11) | 0.0106 (8) | −0.0129 (10) |
C14 | 0.0833 (14) | 0.0608 (12) | 0.0738 (12) | 0.0049 (10) | 0.0043 (11) | 0.0214 (10) |
C15 | 0.0575 (10) | 0.0494 (9) | 0.0655 (10) | −0.0025 (8) | −0.0012 (9) | −0.0146 (8) |
C16 | 0.0539 (11) | 0.1208 (19) | 0.0537 (11) | −0.0224 (12) | 0.0009 (9) | −0.0185 (12) |
C17 | 0.0844 (17) | 0.147 (3) | 0.0600 (13) | −0.0186 (16) | −0.0166 (11) | −0.0009 (15) |
O1—C12 | 1.200 (2) | C6—C7 | 1.491 (2) |
O2—C8 | 1.4484 (19) | C7—C8 | 1.511 (2) |
O2—C12 | 1.354 (2) | C7—C11 | 1.331 (2) |
O3—C6 | 1.4501 (18) | C8—C9 | 1.506 (2) |
O3—C15 | 1.364 (2) | C9—H9A | 0.9700 |
O4—C15 | 1.204 (2) | C9—H9B | 0.9700 |
O5—C8 | 1.3894 (19) | C9—C10 | 1.533 (2) |
O5—C16 | 1.427 (2) | C10—H10 | 0.9800 |
C1—H1A | 0.9700 | C11—C12 | 1.487 (3) |
C1—H1B | 0.9700 | C11—C13 | 1.495 (2) |
C1—C2 | 1.525 (3) | C13—H13A | 0.9600 |
C1—C10 | 1.536 (2) | C13—H13B | 0.9600 |
C2—H2A | 0.9700 | C13—H13C | 0.9600 |
C2—H2B | 0.9700 | C14—H14A | 0.9600 |
C2—C3 | 1.485 (3) | C14—H14B | 0.9600 |
C3—H3 | 0.9300 | C14—H14C | 0.9600 |
C3—C4 | 1.332 (3) | C16—H16A | 0.9700 |
C4—C5 | 1.498 (2) | C16—H16B | 0.9700 |
C4—C15 | 1.468 (3) | C16—C17 | 1.452 (3) |
C5—C6 | 1.566 (2) | C17—H17A | 0.9600 |
C5—C10 | 1.538 (2) | C17—H17B | 0.9600 |
C5—C14 | 1.541 (2) | C17—H17C | 0.9600 |
C6—H6 | 0.9800 | ||
C12—O2—C8 | 109.65 (12) | C8—C9—C10 | 110.33 (13) |
C15—O3—C6 | 109.44 (12) | H9A—C9—H9B | 108.1 |
C8—O5—C16 | 116.95 (13) | C10—C9—H9A | 109.6 |
H1A—C1—H1B | 107.7 | C10—C9—H9B | 109.6 |
C2—C1—H1A | 108.8 | C1—C10—C5 | 108.51 (14) |
C2—C1—H1B | 108.8 | C1—C10—H10 | 108.2 |
C2—C1—C10 | 113.74 (15) | C5—C10—H10 | 108.2 |
C10—C1—H1A | 108.8 | C9—C10—C1 | 110.51 (14) |
C10—C1—H1B | 108.8 | C9—C10—C5 | 112.97 (13) |
C1—C2—H2A | 108.8 | C9—C10—H10 | 108.2 |
C1—C2—H2B | 108.8 | C7—C11—C12 | 107.26 (14) |
H2A—C2—H2B | 107.7 | C7—C11—C13 | 133.06 (18) |
C3—C2—C1 | 113.69 (16) | C12—C11—C13 | 119.65 (17) |
C3—C2—H2A | 108.8 | O1—C12—O2 | 121.74 (18) |
C3—C2—H2B | 108.8 | O1—C12—C11 | 129.02 (18) |
C2—C3—H3 | 119.2 | O2—C12—C11 | 109.25 (14) |
C4—C3—C2 | 121.60 (18) | C11—C13—H13A | 109.5 |
C4—C3—H3 | 119.2 | C11—C13—H13B | 109.5 |
C3—C4—C5 | 125.64 (16) | C11—C13—H13C | 109.5 |
C3—C4—C15 | 126.34 (18) | H13A—C13—H13B | 109.5 |
C15—C4—C5 | 107.69 (15) | H13A—C13—H13C | 109.5 |
C4—C5—C6 | 98.85 (13) | H13B—C13—H13C | 109.5 |
C4—C5—C10 | 110.65 (14) | C5—C14—H14A | 109.5 |
C4—C5—C14 | 110.58 (15) | C5—C14—H14B | 109.5 |
C10—C5—C6 | 117.14 (13) | C5—C14—H14C | 109.5 |
C10—C5—C14 | 110.67 (15) | H14A—C14—H14B | 109.5 |
C14—C5—C6 | 108.35 (14) | H14A—C14—H14C | 109.5 |
O3—C6—C5 | 104.38 (13) | H14B—C14—H14C | 109.5 |
O3—C6—H6 | 109.7 | O3—C15—C4 | 108.67 (14) |
O3—C6—C7 | 110.13 (12) | O4—C15—O3 | 120.78 (18) |
C5—C6—H6 | 109.7 | O4—C15—C4 | 130.56 (19) |
C7—C6—C5 | 112.97 (12) | O5—C16—H16A | 109.7 |
C7—C6—H6 | 109.7 | O5—C16—H16B | 109.7 |
C6—C7—C8 | 116.21 (13) | O5—C16—C17 | 109.64 (19) |
C11—C7—C6 | 133.40 (14) | H16A—C16—H16B | 108.2 |
C11—C7—C8 | 110.06 (14) | C17—C16—H16A | 109.7 |
O2—C8—C7 | 103.73 (12) | C17—C16—H16B | 109.7 |
O2—C8—C9 | 111.14 (14) | C16—C17—H17A | 109.5 |
O5—C8—O2 | 109.54 (13) | C16—C17—H17B | 109.5 |
O5—C8—C7 | 115.69 (14) | C16—C17—H17C | 109.5 |
O5—C8—C9 | 106.89 (13) | H17A—C17—H17B | 109.5 |
C9—C8—C7 | 109.89 (13) | H17A—C17—H17C | 109.5 |
C8—C9—H9A | 109.6 | H17B—C17—H17C | 109.5 |
C8—C9—H9B | 109.6 | ||
O2—C8—C9—C10 | 176.04 (12) | C7—C11—C12—O1 | 178.38 (19) |
O3—C6—C7—C8 | 157.37 (13) | C7—C11—C12—O2 | −1.6 (2) |
O3—C6—C7—C11 | −15.2 (2) | C8—O2—C12—O1 | −179.84 (17) |
O5—C8—C9—C10 | −64.47 (16) | C8—O2—C12—C11 | 0.15 (19) |
C1—C2—C3—C4 | −8.3 (3) | C8—O5—C16—C17 | 176.9 (2) |
C2—C1—C10—C5 | −58.3 (2) | C8—C7—C11—C12 | 2.34 (18) |
C2—C1—C10—C9 | 66.0 (2) | C8—C7—C11—C13 | −175.70 (18) |
C2—C3—C4—C5 | 1.3 (3) | C8—C9—C10—C1 | −174.70 (14) |
C2—C3—C4—C15 | −171.17 (17) | C8—C9—C10—C5 | −52.92 (19) |
C3—C4—C5—C6 | −146.24 (17) | C10—C1—C2—C3 | 37.6 (2) |
C3—C4—C5—C10 | −22.7 (2) | C10—C5—C6—O3 | −151.01 (14) |
C3—C4—C5—C14 | 100.3 (2) | C10—C5—C6—C7 | −31.4 (2) |
C3—C4—C15—O3 | 160.45 (17) | C11—C7—C8—O2 | −2.24 (17) |
C3—C4—C15—O4 | −20.1 (3) | C11—C7—C8—O5 | −122.21 (15) |
C4—C5—C6—O3 | −32.27 (14) | C11—C7—C8—C9 | 116.66 (15) |
C4—C5—C6—C7 | 87.37 (15) | C12—O2—C8—O5 | 125.24 (14) |
C4—C5—C10—C1 | 48.68 (18) | C12—O2—C8—C7 | 1.17 (17) |
C4—C5—C10—C9 | −74.22 (17) | C12—O2—C8—C9 | −116.86 (15) |
C5—C4—C15—O3 | −13.11 (19) | C13—C11—C12—O1 | −3.3 (3) |
C5—C4—C15—O4 | 166.4 (2) | C13—C11—C12—O2 | 176.75 (15) |
C5—C6—C7—C8 | 41.10 (18) | C14—C5—C6—O3 | 82.97 (16) |
C5—C6—C7—C11 | −131.49 (18) | C14—C5—C6—C7 | −157.39 (14) |
C6—O3—C15—O4 | 171.11 (18) | C14—C5—C10—C1 | −74.25 (19) |
C6—O3—C15—C4 | −9.36 (19) | C14—C5—C10—C9 | 162.84 (15) |
C6—C5—C10—C1 | 160.89 (15) | C15—O3—C6—C5 | 26.98 (17) |
C6—C5—C10—C9 | 38.0 (2) | C15—O3—C6—C7 | −94.55 (16) |
C6—C7—C8—O2 | −176.51 (13) | C15—C4—C5—C6 | 27.38 (16) |
C6—C7—C8—O5 | 63.51 (18) | C15—C4—C5—C10 | 150.88 (14) |
C6—C7—C8—C9 | −57.62 (18) | C15—C4—C5—C14 | −86.13 (17) |
C6—C7—C11—C12 | 175.26 (16) | C16—O5—C8—O2 | −64.2 (2) |
C6—C7—C11—C13 | −2.8 (3) | C16—O5—C8—C7 | 52.5 (2) |
C7—C8—C9—C10 | 61.80 (17) | C16—O5—C8—C9 | 175.24 (17) |
Experimental details
Crystal data | |
Chemical formula | C17H20O5 |
Mr | 304.33 |
Crystal system, space group | Orthorhombic, P212121 |
Temperature (K) | 294 |
a, b, c (Å) | 8.4925 (2), 13.0302 (4), 14.1381 (9) |
V (Å3) | 1564.50 (12) |
Z | 4 |
Radiation type | Cu Kα |
µ (mm−1) | 0.78 |
Crystal size (mm) | 0.33 × 0.28 × 0.12 |
Data collection | |
Diffractometer | Agilent SuperNova (Dual, Cu at zero, Eos) |
Absorption correction | Multi-scan (CrysAlis PRO; Agilent, 2013) |
Tmin, Tmax | 0.743, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 14336, 2994, 2871 |
Rint | 0.027 |
(sin θ/λ)max (Å−1) | 0.613 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.037, 0.103, 1.03 |
No. of reflections | 2994 |
No. of parameters | 202 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.13, −0.18 |
Absolute structure | Flack (1983), 000 Friedel pairs |
Absolute structure parameter | −0.1 (2) |
Computer programs: CrysAlis PRO (Agilent, 2013), SUPERFLIP (Palatinus & Chapuis, 2007), SHELXL97 (Sheldrick, 2008), OLEX2 (Dolomanov et al., 2009).
Acknowledgements
We are grateful to the National Natural Science Foundation of China (No. 21102065), the Natural Science Foundation of Gansu Province, China (No. 1208RJYA029) and the Fundational Research Funds for the Central Universities (Nos. lzujbky-2012–83 and lzujbky-2013–72) for financial support of this research.
References
Agilent (2013). CrysAlis PRO. Agilent Technologies Ltd, Yarnton, England. Google Scholar
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This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
The title compound, 8β-ethoxyeremophil-3,7(11)-diene-8α,12(6α,15)-diolide (Fig. 1), was isolated from the roots of Ligularia lapathifolia (Fei et al., 2007). The title compound is composed of four rings, two six-membered and two five-menbered. The six-membered ring A adopt a half-chair conformation, which has pucking paramaters (Cremer & Pople, 1975; Boeyens, 1978) Q = 0.4766 (19) Å, θ = 130.0 (2)°, φ = 133.8 (3)°. The six-membered ring B adopt a chair conformation with pucking paramaters Q = 0.5073 (17) Å, θ = 22.08 (19)°, φ = 205.7 (5)°. The five-membered ring C is almost planar with a mean torsion angle of 1.50 (8)°. The five-membered ring D adopt an envelope conformation. The A/B ring junction is cis-fused (torsion angle C14—C5—C10—H10 = 43°).