organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

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

(Received 15 May 2013; accepted 5 June 2013; online 12 June 2013)

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 envelope conformation 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[Fei, D.-Q., Li, S.-G., Liu, C.-M., Wu, G. & Gao, K. (2007). J. Nat. Prod. 70, 241-245.]). For pucking paramaters, see: Cremer & Pople (1975[Cremer, D. & Pople, J. A. (1975). J. Am. Chem. Soc. 97, 1354-1358.]); Boeyens (1978[Boeyens, J. C. A. (1978). J. Cryst. Mol. Struct. 8, 317-320.])

[Scheme 1]

Experimental

Crystal data
  • C17H20O5

  • Mr = 304.33

  • Orthorhombic, P 21 21 21

  • a = 8.4925 (2) Å

  • b = 13.0302 (4) Å

  • c = 14.1381 (9) Å

  • V = 1564.50 (12) Å3

  • Z = 4

  • Cu Kα radiation

  • μ = 0.78 mm−1

  • T = 294 K

  • 0.33 × 0.28 × 0.12 mm

Data collection
  • Agilent SuperNova (Dual, Cu at zero, Eos) diffractometer

  • Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2013[Agilent (2013). CrysAlis PRO. Agilent Technologies Ltd, Yarnton, England.]) Tmin = 0.743, Tmax = 1.000

  • 14336 measured reflections

  • 2994 independent reflections

  • 2871 reflections with I > 2σ(I)

  • Rint = 0.027

Refinement
  • R[F2 > 2σ(F2)] = 0.037

  • wR(F2) = 0.103

  • S = 1.03

  • 2994 reflections

  • 202 parameters

  • H-atom parameters constrained

  • Δρmax = 0.13 e Å−3

  • Δρmin = −0.18 e Å−3

  • Absolute structure: Flack (1983[Flack, H. D. (1983). Acta Cryst. A39, 876-881.])

  • Flack parameter: −0.1 (2)

Data collection: CrysAlis PRO (Agilent, 2013[Agilent (2013). CrysAlis PRO. Agilent Technologies Ltd, Yarnton, England.]); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SUPERFLIP (Palatinus & Chapuis, 2007[Palatinus, L. & Chapuis, G. (2007). J. Appl. Cryst. 40, 786-790.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: OLEX2 (Dolomanov et al., 2009[Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339-341.]); software used to prepare material for publication: OLEX2.

Supporting information


Comment top

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°).

Related literature top

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 top

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.

Refinement top

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 Flack parameter tentatively indicates the absolute structure.

Computing details top

Data collection: CrysAlis PRO (Agilent, 2013); cell refinement: 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).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, showing displacement ellipsoids at the 30% probability level.
8β-Ethoxyeremophil-3,7(11)-diene-8α,12;6α,15-diolide top
Crystal data top
C17H20O5Dx = 1.292 Mg m3
Mr = 304.33Cu Kα radiation, λ = 1.5418 Å
Orthorhombic, P212121Cell parameters from 9242 reflections
a = 8.4925 (2) Åθ = 4.6–70.7°
b = 13.0302 (4) ŵ = 0.78 mm1
c = 14.1381 (9) ÅT = 294 K
V = 1564.50 (12) Å3Block, colourless
Z = 40.33 × 0.28 × 0.12 mm
F(000) = 648
Data collection top
Agilent SuperNova (Dual, Cu at zero, Eos)
diffractometer
2994 independent reflections
Radiation source: SuperNova (Cu) X-ray Source2871 reflections with I > 2σ(I)
Mirror monochromatorRint = 0.027
Detector resolution: 16.0733 pixels mm-1θmax = 70.8°, θmin = 4.6°
ω scansh = 109
Absorption correction: multi-scan
(CrysAlis PRO; Agilent, 2013)
k = 1515
Tmin = 0.743, Tmax = 1.000l = 1617
14336 measured reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.037H-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 reflectionsΔρmax = 0.13 e Å3
202 parametersΔρmin = 0.18 e Å3
0 restraintsAbsolute structure: Flack (1983), 000 Friedel pairs
Primary atom site location: iterativeAbsolute structure parameter: 0.1 (2)
Crystal data top
C17H20O5V = 1564.50 (12) Å3
Mr = 304.33Z = 4
Orthorhombic, P212121Cu Kα radiation
a = 8.4925 (2) ŵ = 0.78 mm1
b = 13.0302 (4) ÅT = 294 K
c = 14.1381 (9) Å0.33 × 0.28 × 0.12 mm
Data collection top
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 = 1.000Rint = 0.027
14336 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.037H-atom parameters constrained
wR(F2) = 0.103Δρmax = 0.13 e Å3
S = 1.03Δρmin = 0.18 e Å3
2994 reflectionsAbsolute structure: Flack (1983), 000 Friedel pairs
202 parametersAbsolute structure parameter: 0.1 (2)
0 restraints
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
O10.9183 (2)0.64050 (12)0.11330 (10)0.0794 (4)
O20.79269 (15)0.60175 (8)0.24732 (9)0.0556 (3)
O30.82873 (14)0.24550 (10)0.20230 (9)0.0580 (3)
O40.6780 (2)0.17448 (13)0.09057 (11)0.0839 (5)
O50.81102 (14)0.52062 (10)0.39285 (7)0.0514 (3)
C10.3694 (2)0.36787 (16)0.35509 (16)0.0642 (5)
H1A0.34870.30850.39450.077*
H1B0.31330.42570.38220.077*
C20.3051 (2)0.34733 (16)0.25617 (17)0.0678 (5)
H2A0.20710.30960.26170.081*
H2B0.28180.41240.22600.081*
C30.4146 (2)0.28847 (14)0.19487 (14)0.0582 (4)
H30.37950.26500.13650.070*
C40.5619 (2)0.26851 (12)0.22151 (12)0.0484 (4)
C50.63488 (19)0.29910 (12)0.31377 (12)0.0467 (4)
C60.80727 (18)0.31837 (12)0.27873 (11)0.0457 (4)
H60.88170.30340.32990.055*
C70.83272 (17)0.42502 (11)0.24365 (11)0.0416 (3)
C80.75684 (19)0.50977 (12)0.30066 (11)0.0436 (3)
C90.58186 (19)0.49238 (12)0.30652 (12)0.0460 (4)
H9A0.53760.49070.24330.055*
H9B0.53310.54860.34070.055*
C100.5468 (2)0.39090 (12)0.35713 (12)0.0481 (4)
H100.57940.39770.42330.058*
C110.89795 (19)0.46356 (14)0.16573 (11)0.0485 (4)
C120.8750 (2)0.57663 (15)0.16860 (12)0.0551 (4)
C130.9784 (2)0.4157 (2)0.08268 (13)0.0680 (5)
H13A1.00690.34630.09780.102*
H13B1.07150.45410.06760.102*
H13C0.90850.41590.02930.102*
C140.6368 (3)0.20772 (17)0.38296 (16)0.0726 (6)
H14A0.68740.22790.44080.109*
H14B0.69350.15160.35510.109*
H14C0.53070.18670.39610.109*
C150.6863 (2)0.22373 (14)0.16241 (14)0.0575 (4)
C160.9771 (2)0.5300 (2)0.40545 (14)0.0762 (7)
H16A1.01630.58730.36860.091*
H16B1.02900.46810.38350.091*
C171.0122 (3)0.5461 (3)0.50483 (17)0.0970 (9)
H17A1.12370.54060.51480.146*
H17B0.95880.49530.54200.146*
H17C0.97730.61330.52340.146*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0966 (11)0.0798 (10)0.0619 (8)0.0179 (9)0.0110 (8)0.0133 (8)
O20.0652 (7)0.0444 (6)0.0572 (7)0.0037 (5)0.0106 (6)0.0012 (5)
O30.0483 (6)0.0539 (6)0.0718 (7)0.0118 (5)0.0004 (6)0.0224 (6)
O40.0807 (10)0.0882 (11)0.0828 (10)0.0103 (9)0.0044 (8)0.0454 (9)
O50.0490 (6)0.0629 (7)0.0422 (6)0.0064 (5)0.0061 (5)0.0128 (5)
C10.0469 (9)0.0657 (12)0.0800 (13)0.0003 (9)0.0186 (9)0.0034 (10)
C20.0406 (8)0.0616 (10)0.1014 (15)0.0028 (8)0.0023 (10)0.0036 (11)
C30.0480 (9)0.0559 (9)0.0707 (11)0.0084 (7)0.0062 (8)0.0015 (9)
C40.0457 (8)0.0414 (8)0.0580 (9)0.0049 (6)0.0002 (7)0.0044 (7)
C50.0457 (8)0.0435 (8)0.0510 (9)0.0038 (6)0.0009 (7)0.0012 (7)
C60.0404 (7)0.0469 (8)0.0497 (8)0.0094 (6)0.0042 (7)0.0087 (7)
C70.0349 (7)0.0486 (8)0.0412 (7)0.0026 (6)0.0023 (6)0.0095 (6)
C80.0452 (8)0.0428 (8)0.0427 (8)0.0009 (6)0.0051 (6)0.0042 (6)
C90.0431 (8)0.0442 (8)0.0508 (8)0.0066 (6)0.0069 (7)0.0044 (7)
C100.0462 (8)0.0507 (9)0.0474 (8)0.0020 (7)0.0096 (7)0.0004 (7)
C110.0405 (8)0.0662 (10)0.0387 (8)0.0000 (7)0.0016 (6)0.0077 (7)
C120.0544 (10)0.0647 (10)0.0462 (9)0.0088 (8)0.0015 (7)0.0037 (8)
C130.0609 (11)0.0976 (15)0.0454 (9)0.0077 (11)0.0106 (8)0.0129 (10)
C140.0833 (14)0.0608 (12)0.0738 (12)0.0049 (10)0.0043 (11)0.0214 (10)
C150.0575 (10)0.0494 (9)0.0655 (10)0.0025 (8)0.0012 (9)0.0146 (8)
C160.0539 (11)0.1208 (19)0.0537 (11)0.0224 (12)0.0009 (9)0.0185 (12)
C170.0844 (17)0.147 (3)0.0600 (13)0.0186 (16)0.0166 (11)0.0009 (15)
Geometric parameters (Å, º) top
O1—C121.200 (2)C6—C71.491 (2)
O2—C81.4484 (19)C7—C81.511 (2)
O2—C121.354 (2)C7—C111.331 (2)
O3—C61.4501 (18)C8—C91.506 (2)
O3—C151.364 (2)C9—H9A0.9700
O4—C151.204 (2)C9—H9B0.9700
O5—C81.3894 (19)C9—C101.533 (2)
O5—C161.427 (2)C10—H100.9800
C1—H1A0.9700C11—C121.487 (3)
C1—H1B0.9700C11—C131.495 (2)
C1—C21.525 (3)C13—H13A0.9600
C1—C101.536 (2)C13—H13B0.9600
C2—H2A0.9700C13—H13C0.9600
C2—H2B0.9700C14—H14A0.9600
C2—C31.485 (3)C14—H14B0.9600
C3—H30.9300C14—H14C0.9600
C3—C41.332 (3)C16—H16A0.9700
C4—C51.498 (2)C16—H16B0.9700
C4—C151.468 (3)C16—C171.452 (3)
C5—C61.566 (2)C17—H17A0.9600
C5—C101.538 (2)C17—H17B0.9600
C5—C141.541 (2)C17—H17C0.9600
C6—H60.9800
C12—O2—C8109.65 (12)C8—C9—C10110.33 (13)
C15—O3—C6109.44 (12)H9A—C9—H9B108.1
C8—O5—C16116.95 (13)C10—C9—H9A109.6
H1A—C1—H1B107.7C10—C9—H9B109.6
C2—C1—H1A108.8C1—C10—C5108.51 (14)
C2—C1—H1B108.8C1—C10—H10108.2
C2—C1—C10113.74 (15)C5—C10—H10108.2
C10—C1—H1A108.8C9—C10—C1110.51 (14)
C10—C1—H1B108.8C9—C10—C5112.97 (13)
C1—C2—H2A108.8C9—C10—H10108.2
C1—C2—H2B108.8C7—C11—C12107.26 (14)
H2A—C2—H2B107.7C7—C11—C13133.06 (18)
C3—C2—C1113.69 (16)C12—C11—C13119.65 (17)
C3—C2—H2A108.8O1—C12—O2121.74 (18)
C3—C2—H2B108.8O1—C12—C11129.02 (18)
C2—C3—H3119.2O2—C12—C11109.25 (14)
C4—C3—C2121.60 (18)C11—C13—H13A109.5
C4—C3—H3119.2C11—C13—H13B109.5
C3—C4—C5125.64 (16)C11—C13—H13C109.5
C3—C4—C15126.34 (18)H13A—C13—H13B109.5
C15—C4—C5107.69 (15)H13A—C13—H13C109.5
C4—C5—C698.85 (13)H13B—C13—H13C109.5
C4—C5—C10110.65 (14)C5—C14—H14A109.5
C4—C5—C14110.58 (15)C5—C14—H14B109.5
C10—C5—C6117.14 (13)C5—C14—H14C109.5
C10—C5—C14110.67 (15)H14A—C14—H14B109.5
C14—C5—C6108.35 (14)H14A—C14—H14C109.5
O3—C6—C5104.38 (13)H14B—C14—H14C109.5
O3—C6—H6109.7O3—C15—C4108.67 (14)
O3—C6—C7110.13 (12)O4—C15—O3120.78 (18)
C5—C6—H6109.7O4—C15—C4130.56 (19)
C7—C6—C5112.97 (12)O5—C16—H16A109.7
C7—C6—H6109.7O5—C16—H16B109.7
C6—C7—C8116.21 (13)O5—C16—C17109.64 (19)
C11—C7—C6133.40 (14)H16A—C16—H16B108.2
C11—C7—C8110.06 (14)C17—C16—H16A109.7
O2—C8—C7103.73 (12)C17—C16—H16B109.7
O2—C8—C9111.14 (14)C16—C17—H17A109.5
O5—C8—O2109.54 (13)C16—C17—H17B109.5
O5—C8—C7115.69 (14)C16—C17—H17C109.5
O5—C8—C9106.89 (13)H17A—C17—H17B109.5
C9—C8—C7109.89 (13)H17A—C17—H17C109.5
C8—C9—H9A109.6H17B—C17—H17C109.5
C8—C9—H9B109.6
O2—C8—C9—C10176.04 (12)C7—C11—C12—O1178.38 (19)
O3—C6—C7—C8157.37 (13)C7—C11—C12—O21.6 (2)
O3—C6—C7—C1115.2 (2)C8—O2—C12—O1179.84 (17)
O5—C8—C9—C1064.47 (16)C8—O2—C12—C110.15 (19)
C1—C2—C3—C48.3 (3)C8—O5—C16—C17176.9 (2)
C2—C1—C10—C558.3 (2)C8—C7—C11—C122.34 (18)
C2—C1—C10—C966.0 (2)C8—C7—C11—C13175.70 (18)
C2—C3—C4—C51.3 (3)C8—C9—C10—C1174.70 (14)
C2—C3—C4—C15171.17 (17)C8—C9—C10—C552.92 (19)
C3—C4—C5—C6146.24 (17)C10—C1—C2—C337.6 (2)
C3—C4—C5—C1022.7 (2)C10—C5—C6—O3151.01 (14)
C3—C4—C5—C14100.3 (2)C10—C5—C6—C731.4 (2)
C3—C4—C15—O3160.45 (17)C11—C7—C8—O22.24 (17)
C3—C4—C15—O420.1 (3)C11—C7—C8—O5122.21 (15)
C4—C5—C6—O332.27 (14)C11—C7—C8—C9116.66 (15)
C4—C5—C6—C787.37 (15)C12—O2—C8—O5125.24 (14)
C4—C5—C10—C148.68 (18)C12—O2—C8—C71.17 (17)
C4—C5—C10—C974.22 (17)C12—O2—C8—C9116.86 (15)
C5—C4—C15—O313.11 (19)C13—C11—C12—O13.3 (3)
C5—C4—C15—O4166.4 (2)C13—C11—C12—O2176.75 (15)
C5—C6—C7—C841.10 (18)C14—C5—C6—O382.97 (16)
C5—C6—C7—C11131.49 (18)C14—C5—C6—C7157.39 (14)
C6—O3—C15—O4171.11 (18)C14—C5—C10—C174.25 (19)
C6—O3—C15—C49.36 (19)C14—C5—C10—C9162.84 (15)
C6—C5—C10—C1160.89 (15)C15—O3—C6—C526.98 (17)
C6—C5—C10—C938.0 (2)C15—O3—C6—C794.55 (16)
C6—C7—C8—O2176.51 (13)C15—C4—C5—C627.38 (16)
C6—C7—C8—O563.51 (18)C15—C4—C5—C10150.88 (14)
C6—C7—C8—C957.62 (18)C15—C4—C5—C1486.13 (17)
C6—C7—C11—C12175.26 (16)C16—O5—C8—O264.2 (2)
C6—C7—C11—C132.8 (3)C16—O5—C8—C752.5 (2)
C7—C8—C9—C1061.80 (17)C16—O5—C8—C9175.24 (17)

Experimental details

Crystal data
Chemical formulaC17H20O5
Mr304.33
Crystal system, space groupOrthorhombic, P212121
Temperature (K)294
a, b, c (Å)8.4925 (2), 13.0302 (4), 14.1381 (9)
V3)1564.50 (12)
Z4
Radiation typeCu Kα
µ (mm1)0.78
Crystal size (mm)0.33 × 0.28 × 0.12
Data collection
DiffractometerAgilent SuperNova (Dual, Cu at zero, Eos)
diffractometer
Absorption correctionMulti-scan
(CrysAlis PRO; Agilent, 2013)
Tmin, Tmax0.743, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections
14336, 2994, 2871
Rint0.027
(sin θ/λ)max1)0.613
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.037, 0.103, 1.03
No. of reflections2994
No. of parameters202
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.13, 0.18
Absolute structureFlack (1983), 000 Friedel pairs
Absolute structure parameter0.1 (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

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