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Acta Crystallographica Section E: Structure Reports Online logoLink to Acta Crystallographica Section E: Structure Reports Online
. 2012 Aug 1;68(Pt 9):o2612–o2613. doi: 10.1107/S1600536812033636

(1R,4R,5aS,7S,9aS)-7,9a-Dimethyl-6-methyl­ene-3-oxo-1,3,4,5,5a,6,7,8,9,9a-deca­hydro­naphtho­[1,2-c]furan-1,4-diyl diacetate

Mercy Mudyiwa a, Mohamed S Rajab a, Frank R Fronczek a,*, Steven F Watkins a
PMCID: PMC3435643  PMID: 22969516

Abstract

The title compound, C19H24O6, is a sesquiterpene lactone isolated from the Kenyan plant Warburgia ugandensis. Ring A adopts a chair conformation, ring B is in a C 2 twist conformation and the lactone ring is nearly planar with maximum deviation 0.007 (1) Å. The reported absolute configuration is based on that of the similar compound bromo-parasiticolide A and is supported by analysis of Bijvoet differences from light atoms in Mo Kα radiation.

Related literature  

For related structures, see: Fukuyama et al. (1975 ▶) (Bromo-parasiticolide A; PARASB); Ikhiri et al. (1995 ▶) (ZOXLIH); Aranda et al. (2001 ▶) (ABUKIR); King et al. (1973 ▶) (PRPRDE); Rossmann & Lipscomb (1958 ▶) (IRSBBZ); Rahbaek et al. (1997 ▶) (NEYKOR), Zhang et al. (2006 ▶) (UCOLAA, UCOKUT); Harinantenaina et al. (2007 ▶) (NIDJUG); McCorkindale et al. (1981 ▶) (PEBRLD); Hayashi et al. (2010 ▶) (VUTCIX). For the absolute configuration of sesquiterpene lactones, see: Fischer et al. (1979 ▶). For a description of the Cambridge Structural Database, see: Allen (2002 ▶). For the absolute configuration from Bijvoet pairs, see: Hooft et al. (2008 ▶). For compounds from Warburgia ugandensis, see: Wube et al. (2005 ▶) and for related compounds, see: Garland (1969 ▶); Kokwaro (1976 ▶).graphic file with name e-68-o2612-scheme1.jpg

Experimental  

Crystal data  

  • C19H24O6

  • M r = 348.38

  • Tetragonal, Inline graphic

  • a = 13.014 (2) Å

  • c = 21.167 (3) Å

  • V = 3584.9 (9) Å3

  • Z = 8

  • Mo Kα radiation

  • μ = 0.10 mm−1

  • T = 100 K

  • 0.37 × 0.25 × 0.25 mm

Data collection  

  • Nonius KappaCCD diffractometer

  • Absorption correction: multi-scan (SCALEPACK; Otwinowski & Minor, 1997 ▶) T min = 0.966, T max = 0.977

  • 11378 measured reflections

  • 6507 independent reflections

  • 5934 reflections with I > 2σ(I)

  • R int = 0.021

Refinement  

  • R[F 2 > 2σ(F 2)] = 0.036

  • wR(F 2) = 0.092

  • S = 1.02

  • 6507 reflections

  • 231 parameters

  • H-atom parameters constrained

  • Δρmax = 0.28 e Å−3

  • Δρmin = −0.21 e Å−3

  • Absolute structure: Flack (1983 ▶). 2776 Bijvoet pairs

  • Flack parameter: 0.4 (6)

Data collection: COLLECT (Nonius, 2000 ▶); cell refinement: DENZO and SCALEPACK (Otwinowski & Minor, 1997 ▶); data reduction: DENZO and SCALEPACK; program(s) used to solve structure: SIR2002 (Burla et al., 2003 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812033636/bt5979sup1.cif

e-68-o2612-sup1.cif (20.1KB, cif)

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812033636/bt5979Isup2.hkl

e-68-o2612-Isup2.hkl (312.2KB, hkl)

Supplementary material file. DOI: 10.1107/S1600536812033636/bt5979Isup3.cml

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

Acknowledgments

Purchase of the diffractometer was made possible by grant No. LEQSF(1999–2000)-ESH-TR-13, administered by the Louisiana Board of Regents.

supplementary crystallographic information

Comment

Coloratanolide and drimanolide sesquiterpene lactones, such as title compound I, have been isolated from the stem bark of Warburgia ugandensis Sprague (Canellaceae) as described by Wube et al. (2005). Plants of the genus Warburgia are of interest because of their use by herbalists in Kenya for the treatment of a number of parasitic diseases (Kokwaro, 1976). Compound I is the first sesquiterpene lactone to be crystallographically characterized which has the coloratanolide skeleton, (CAS 60306–54-9). The absolute configuration reported herein is based on the configuration of bromo-parasiticolide A (Fukuyama et al., 1975), CCDC refcode PARASB (Allen, 2002), and supported by analysis of 2776 Bijvoet pairs.

Experimental

Compound I was isolated from the stem bark of Warburgia ugandensis Sprague (Canellaceae) collected in Eldoret, Uasin Gishu District, Kenya. Crystals suitable for diffraction were grown from acetone/hexane/ethyl ether.

Refinement

H atoms were placed in calculated positions, guided by difference maps, with C—H bond distances 0.95–1.00 Å, Uiso = 1.2Ueq of the attached carbon atom (1.5 for methyl), and thereafter treated as riding. A torsional parameter was refined for each methyl group.

The absolute configuration and space group assignment were established in part by analysis of 2776 Bijvoet pairs. Although the refined Flack parameter x = 0.4 (6) (Flack, 1983) is not definitive, the Hooft parameter y = 0.1 (3) and Hooft P2(true) = 0.998 (Hooft et al., 2008) are strong indicators that the reported configuration is correct. This configuration is consistent with that of bromo-parasiticolide A (Fukuyama et al., 1975), CCDC refcode PARASB (Allen, 2002) and with the accepted configuration of sesquiterpene lactones from higher plants (Fischer et al., 1979).

Figures

Fig. 1.

Fig. 1.

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View of (I) (50% probability displacement ellipsoids)

Crystal data

C19H24O6 Dx = 1.291 Mg m−3
Mr = 348.38 Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P43212 Cell parameters from 6310 reflections
Hall symbol: P 4nw 2abw θ = 2.5–32.6°
a = 13.014 (2) Å µ = 0.10 mm−1
c = 21.167 (3) Å T = 100 K
V = 3584.9 (9) Å3 Prism, colorless
Z = 8 0.37 × 0.25 × 0.25 mm
F(000) = 1488
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Data collection

Nonius KappaCCD diffractometer 6507 independent reflections
Radiation source: sealed tube 5934 reflections with I > 2σ(I)
Horizonally mounted graphite crystal monochromator Rint = 0.021
Detector resolution: 9 pixels mm-1 θmax = 32.6°, θmin = 3.1°
φ and ω scans h = −19→19
Absorption correction: multi-scan (SCALEPACK; Otwinowski & Minor, 1997) k = −13→13
Tmin = 0.966, Tmax = 0.977 l = −30→31
11378 measured reflections
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Refinement

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)] = 0.036 H-atom parameters constrained
wR(F2) = 0.092 w = 1/[σ2(Fo2) + (0.0489P)2 + 0.548P] where P = (Fo2 + 2Fc2)/3
S = 1.02 (Δ/σ)max = 0.001
6507 reflections Δρmax = 0.28 e Å−3
231 parameters Δρmin = −0.21 e Å−3
0 restraints Absolute structure: Flack (1983). 2776 Bijvoet pairs
0 constraints Flack parameter: 0.4 (6)
Primary atom site location: structure-invariant direct methods
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Special details

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.
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Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2)

x y z Uiso*/Ueq
C1 0.99387 (7) 0.15194 (7) 0.38460 (4) 0.01487 (16)
C2 1.10097 (8) 0.17487 (8) 0.41219 (5) 0.01852 (17)
H2A 1.1216 0.2454 0.4001 0.022*
H2B 1.0972 0.172 0.4589 0.022*
C3 1.18311 (8) 0.09896 (9) 0.38923 (5) 0.02218 (19)
H3A 1.2483 0.1131 0.4117 0.027*
H3B 1.1952 0.11 0.3436 0.027*
C4 1.15268 (8) −0.01396 (8) 0.40011 (5) 0.02003 (18)
H4 1.1451 −0.0238 0.4467 0.024*
C5 1.04822 (8) −0.03292 (8) 0.37083 (4) 0.01737 (17)
C6 0.96687 (7) 0.03709 (7) 0.39832 (4) 0.01477 (15)
H6 0.9717 0.0288 0.4452 0.018*
C7 0.85545 (7) 0.01232 (8) 0.38106 (4) 0.01717 (17)
H7A 0.8433 −0.0624 0.3855 0.021*
H7B 0.8425 0.0315 0.3365 0.021*
C8 0.78177 (8) 0.07130 (7) 0.42426 (4) 0.01629 (17)
H8 0.711 0.0714 0.4058 0.02*
C9 0.81884 (7) 0.17881 (7) 0.43274 (4) 0.01617 (16)
C10 0.75719 (8) 0.26445 (8) 0.45837 (5) 0.01949 (18)
C11 0.91383 (8) 0.32891 (8) 0.42864 (5) 0.01760 (17)
H11 0.9261 0.3685 0.3889 0.021*
C12 0.91114 (7) 0.21474 (7) 0.41591 (4) 0.01502 (16)
C13 0.99210 (8) 0.17746 (8) 0.31324 (4) 0.02007 (18)
H13A 0.9224 0.1675 0.2967 0.03*
H13B 1.0398 0.1319 0.2908 0.03*
H13C 1.013 0.2491 0.3069 0.03*
C14 1.23690 (9) −0.08734 (10) 0.37789 (6) 0.0301 (2)
H14A 1.216 −0.1583 0.3865 0.045*
H14B 1.3008 −0.0722 0.4005 0.045*
H14C 1.2478 −0.0785 0.3324 0.045*
C15 1.02974 (9) −0.10108 (9) 0.32528 (5) 0.0227 (2)
H15A 0.9625 −0.1076 0.3083 0.027*
H15B 1.0838 −0.1431 0.3098 0.027*
C16 1.02993 (9) 0.44956 (8) 0.47234 (5) 0.02094 (19)
C17 1.10061 (10) 0.46776 (9) 0.52658 (5) 0.0266 (2)
H17A 1.139 0.5315 0.5196 0.04*
H17B 1.1487 0.4101 0.5302 0.04*
H17C 1.0605 0.4736 0.5656 0.04*
C18 0.71756 (8) −0.05724 (8) 0.49413 (5) 0.02047 (18)
C19 0.72455 (9) −0.10197 (10) 0.55937 (5) 0.0262 (2)
H19A 0.6552 −0.1138 0.5759 0.039*
H19B 0.7611 −0.054 0.5871 0.039*
H19C 0.7619 −0.1673 0.5577 0.039*
O1 1.00912 (8) 0.50921 (7) 0.43108 (4) 0.0327 (2)
O2 0.98905 (6) 0.35231 (6) 0.47497 (3) 0.01904 (14)
O3 0.81477 (6) 0.35250 (6) 0.45508 (4) 0.02120 (15)
O4 0.67051 (6) 0.26478 (7) 0.47800 (4) 0.02641 (17)
O5 0.78024 (6) 0.02495 (6) 0.48730 (3) 0.01794 (14)
O6 0.66441 (8) −0.09022 (8) 0.45248 (4) 0.0323 (2)
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Atomic displacement parameters (Å2)

U11 U22 U33 U12 U13 U23
C1 0.0147 (4) 0.0157 (4) 0.0142 (4) −0.0010 (3) −0.0002 (3) 0.0010 (3)
C2 0.0154 (4) 0.0190 (4) 0.0212 (4) −0.0020 (3) −0.0014 (3) −0.0006 (4)
C3 0.0148 (4) 0.0253 (5) 0.0265 (5) 0.0002 (4) 0.0006 (4) −0.0006 (4)
C4 0.0184 (4) 0.0222 (5) 0.0195 (4) 0.0046 (3) 0.0007 (3) −0.0013 (3)
C5 0.0191 (4) 0.0171 (4) 0.0159 (4) 0.0011 (3) 0.0017 (3) 0.0018 (3)
C6 0.0154 (4) 0.0153 (4) 0.0137 (4) −0.0006 (3) 0.0001 (3) 0.0005 (3)
C7 0.0178 (4) 0.0176 (4) 0.0161 (4) −0.0031 (3) −0.0002 (3) −0.0014 (3)
C8 0.0149 (4) 0.0186 (4) 0.0154 (4) −0.0019 (3) −0.0008 (3) 0.0012 (3)
C9 0.0158 (4) 0.0168 (4) 0.0160 (4) 0.0010 (3) −0.0007 (3) −0.0002 (3)
C10 0.0187 (4) 0.0206 (4) 0.0192 (4) 0.0020 (3) −0.0018 (3) −0.0011 (3)
C11 0.0185 (4) 0.0165 (4) 0.0178 (4) 0.0004 (3) −0.0019 (3) 0.0008 (3)
C12 0.0162 (4) 0.0152 (4) 0.0137 (4) 0.0005 (3) −0.0020 (3) 0.0008 (3)
C13 0.0241 (5) 0.0214 (4) 0.0147 (4) −0.0002 (4) 0.0017 (3) 0.0038 (3)
C14 0.0222 (5) 0.0337 (6) 0.0342 (6) 0.0087 (4) 0.0005 (4) −0.0060 (5)
C15 0.0255 (5) 0.0218 (5) 0.0208 (4) 0.0002 (4) 0.0027 (4) −0.0028 (4)
C16 0.0249 (5) 0.0159 (4) 0.0220 (4) −0.0026 (4) 0.0036 (4) −0.0028 (3)
C17 0.0311 (6) 0.0235 (5) 0.0253 (5) −0.0089 (4) −0.0024 (4) −0.0033 (4)
C18 0.0191 (4) 0.0222 (4) 0.0202 (4) −0.0040 (4) 0.0008 (4) 0.0028 (4)
C19 0.0248 (5) 0.0304 (6) 0.0233 (5) −0.0026 (4) −0.0003 (4) 0.0089 (4)
O1 0.0492 (6) 0.0191 (4) 0.0299 (4) −0.0068 (4) −0.0052 (4) 0.0050 (3)
O2 0.0226 (4) 0.0154 (3) 0.0191 (3) −0.0040 (3) −0.0034 (3) 0.0015 (2)
O3 0.0197 (3) 0.0178 (3) 0.0261 (3) 0.0027 (3) 0.0010 (3) −0.0020 (3)
O4 0.0181 (3) 0.0295 (4) 0.0316 (4) 0.0029 (3) 0.0022 (3) −0.0046 (3)
O5 0.0172 (3) 0.0207 (3) 0.0159 (3) −0.0035 (3) −0.0009 (2) 0.0027 (3)
O6 0.0364 (5) 0.0361 (5) 0.0243 (4) −0.0189 (4) −0.0047 (4) 0.0026 (3)
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Geometric parameters (Å, º)

C1—C12 1.5054 (14) C10—O3 1.3709 (13)
C1—C2 1.5403 (14) C11—O2 1.4187 (12)
C1—C13 1.5468 (13) C11—O3 1.4386 (13)
C1—C6 1.5627 (13) C11—C12 1.5104 (14)
C2—C3 1.5346 (15) C11—H11 1
C2—H2A 0.99 C13—H13A 0.98
C2—H2B 0.99 C13—H13B 0.98
C3—C4 1.5393 (16) C13—H13C 0.98
C3—H3A 0.99 C14—H14A 0.98
C3—H3B 0.99 C14—H14B 0.98
C4—C5 1.5143 (14) C14—H14C 0.98
C4—C14 1.5279 (15) C15—H15A 0.95
C4—H4 1 C15—H15B 0.95
C5—C15 1.3321 (14) C16—O1 1.1994 (14)
C5—C6 1.5131 (13) C16—O2 1.3740 (12)
C6—C7 1.5297 (14) C16—C17 1.4902 (15)
C6—H6 1 C17—H17A 0.98
C7—C8 1.5313 (14) C17—H17B 0.98
C7—H7A 0.99 C17—H17C 0.98
C7—H7B 0.99 C18—O6 1.2000 (13)
C8—O5 1.4646 (12) C18—O5 1.3529 (12)
C8—C9 1.4908 (14) C18—C19 1.5013 (15)
C8—H8 1 C19—H19A 0.98
C9—C12 1.3373 (14) C19—H19B 0.98
C9—C10 1.4766 (14) C19—H19C 0.98
C10—O4 1.2021 (13)
C12—C1—C2 112.03 (8) O4—C10—O3 121.84 (10)
C12—C1—C13 107.62 (8) O4—C10—C9 129.76 (10)
C2—C1—C13 110.01 (8) O3—C10—C9 108.37 (8)
C12—C1—C6 106.06 (7) O2—C11—O3 107.67 (8)
C2—C1—C6 108.56 (8) O2—C11—C12 110.52 (8)
C13—C1—C6 112.55 (8) O3—C11—C12 104.98 (8)
C3—C2—C1 112.68 (8) O2—C11—H11 111.1
C3—C2—H2A 109.1 O3—C11—H11 111.1
C1—C2—H2A 109.1 C12—C11—H11 111.1
C3—C2—H2B 109.1 C9—C12—C1 124.74 (9)
C1—C2—H2B 109.1 C9—C12—C11 108.49 (9)
H2A—C2—H2B 107.8 C1—C12—C11 126.58 (9)
C2—C3—C4 112.83 (8) C1—C13—H13A 109.5
C2—C3—H3A 109 C1—C13—H13B 109.5
C4—C3—H3A 109 H13A—C13—H13B 109.5
C2—C3—H3B 109 C1—C13—H13C 109.5
C4—C3—H3B 109 H13A—C13—H13C 109.5
H3A—C3—H3B 107.8 H13B—C13—H13C 109.5
C5—C4—C14 114.59 (9) C4—C14—H14A 109.5
C5—C4—C3 108.98 (8) C4—C14—H14B 109.5
C14—C4—C3 111.47 (9) H14A—C14—H14B 109.5
C5—C4—H4 107.1 C4—C14—H14C 109.5
C14—C4—H4 107.1 H14A—C14—H14C 109.5
C3—C4—H4 107.1 H14B—C14—H14C 109.5
C15—C5—C6 123.58 (9) C5—C15—H15A 120
C15—C5—C4 124.53 (9) C5—C15—H15B 120
C6—C5—C4 111.88 (8) H15A—C15—H15B 120
C5—C6—C7 116.39 (8) O1—C16—O2 122.57 (10)
C5—C6—C1 110.31 (8) O1—C16—C17 126.69 (10)
C7—C6—C1 111.73 (8) O2—C16—C17 110.74 (9)
C5—C6—H6 105.9 C16—C17—H17A 109.5
C7—C6—H6 105.9 C16—C17—H17B 109.5
C1—C6—H6 105.9 H17A—C17—H17B 109.5
C6—C7—C8 110.20 (8) C16—C17—H17C 109.5
C6—C7—H7A 109.6 H17A—C17—H17C 109.5
C8—C7—H7A 109.6 H17B—C17—H17C 109.5
C6—C7—H7B 109.6 O6—C18—O5 123.49 (10)
C8—C7—H7B 109.6 O6—C18—C19 124.89 (10)
H7A—C7—H7B 108.1 O5—C18—C19 111.61 (9)
O5—C8—C9 106.34 (7) C18—C19—H19A 109.5
O5—C8—C7 110.25 (8) C18—C19—H19B 109.5
C9—C8—C7 109.86 (8) H19A—C19—H19B 109.5
O5—C8—H8 110.1 C18—C19—H19C 109.5
C9—C8—H8 110.1 H19A—C19—H19C 109.5
C7—C8—H8 110.1 H19B—C19—H19C 109.5
C12—C9—C10 108.79 (9) C16—O2—C11 115.91 (8)
C12—C9—C8 125.92 (9) C10—O3—C11 109.35 (8)
C10—C9—C8 125.23 (9) C18—O5—C8 115.54 (8)
C12—C1—C2—C3 170.06 (8) C8—C9—C10—O4 1.98 (17)
C13—C1—C2—C3 −70.28 (11) C12—C9—C10—O3 1.20 (11)
C6—C1—C2—C3 53.28 (10) C8—C9—C10—O3 −176.04 (9)
C1—C2—C3—C4 −53.11 (12) C10—C9—C12—C1 −176.62 (8)
C2—C3—C4—C5 53.61 (11) C8—C9—C12—C1 0.59 (15)
C2—C3—C4—C14 −178.93 (9) C10—C9—C12—C11 −1.26 (10)
C14—C4—C5—C15 −5.67 (16) C8—C9—C12—C11 175.95 (9)
C3—C4—C5—C15 120.00 (11) C2—C1—C12—C9 −137.96 (10)
C14—C4—C5—C6 175.82 (9) C13—C1—C12—C9 100.99 (11)
C3—C4—C5—C6 −58.51 (10) C6—C1—C12—C9 −19.68 (12)
C15—C5—C6—C7 11.94 (14) C2—C1—C12—C11 47.52 (12)
C4—C5—C6—C7 −169.54 (8) C13—C1—C12—C11 −73.53 (11)
C15—C5—C6—C1 −116.70 (11) C6—C1—C12—C11 165.80 (8)
C4—C5—C6—C1 61.83 (10) O2—C11—C12—C9 116.73 (9)
C12—C1—C6—C5 −177.79 (7) O3—C11—C12—C9 0.90 (10)
C2—C1—C6—C5 −57.24 (9) O2—C11—C12—C1 −68.02 (12)
C13—C1—C6—C5 64.78 (10) O3—C11—C12—C1 176.15 (8)
C12—C1—C6—C7 51.08 (9) O1—C16—O2—C11 −4.93 (15)
C2—C1—C6—C7 171.64 (8) C17—C16—O2—C11 174.94 (9)
C13—C1—C6—C7 −66.34 (10) O3—C11—O2—C16 −92.25 (10)
C5—C6—C7—C8 166.12 (8) C12—C11—O2—C16 153.62 (8)
C1—C6—C7—C8 −65.93 (10) O4—C10—O3—C11 −178.80 (10)
C6—C7—C8—O5 −74.35 (10) C9—C10—O3—C11 −0.60 (11)
C6—C7—C8—C9 42.52 (10) O2—C11—O3—C10 −117.91 (9)
O5—C8—C9—C12 107.52 (10) C12—C11—O3—C10 −0.14 (10)
C7—C8—C9—C12 −11.78 (13) O6—C18—O5—C8 −1.47 (15)
O5—C8—C9—C10 −75.71 (11) C19—C18—O5—C8 177.62 (9)
C7—C8—C9—C10 164.99 (9) C9—C8—O5—C18 158.03 (8)
C12—C9—C10—O4 179.22 (11) C7—C8—O5—C18 −82.93 (10)
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Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: BT5979).

References

  1. Allen, F. H. (2002). Acta Cryst. B58, 380–388. [DOI] [PubMed]
  2. Aranda, G., Moreno, L., Cortes, M., Prange, T., Maurs, M. & Azerad, R. (2001). Tetrahedron, 57, 6051–6056.
  3. Burla, M. C., Camalli, M., Carrozzini, B., Cascarano, G. L., Giacovazzo, C., Polidori, G. & Spagna, R. (2003). J. Appl. Cryst. 36, 1103.
  4. Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.
  5. Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838.
  6. Fischer, N. H., Olivier, E. J. & Fischer, H. D. (1979). Progress in the Chemistry of Organic Natural Products, Vol. 38, edited by W. Hertz, H. Grisebach & G. W. Kirby. Vienna: Springer.
  7. Flack, H. D. (1983). Acta Cryst. A39, 876–881.
  8. Fukuyama, K., Kawai, H., Tsukihara, T., Katsube, Y., Hamasaki, T., Hatsuda, Y. & Kuwano, H. (1975). Bull. Chem. Soc. Jpn, 48, 2949–2950.
  9. Garland, M. T. (1969). An. Fac. Quim. Farm. U. Chile, 21, 108–110.
  10. Harinantenaina, L., Asakawa, Y. & De Clercq, E. (2007). J. Nat. Prod. 70, 277–282. [DOI] [PubMed]
  11. Hayashi, N., Yamamoto, K., Minowa, N., Mitomi, M. & Nakada, M. (2010). Org. Biomol. Chem. 8, 1821–1825. [DOI] [PubMed]
  12. Hooft, R. W. W., Straver, L. H. & Spek, A. L. (2008). J. Appl. Cryst. 41, 96–103. [DOI] [PMC free article] [PubMed]
  13. Ikhiri, K., Mahaman, I., Ahond, A., Chiaroni, A., Poupat, C., Riche, C. & Potier, P. (1995). J. Nat. Prod. 58, 1136–1138.
  14. King, T. J., Roberts, J. C. & Thompson, D. J. (1973). J. Chem. Soc. Perkin Trans. 1, pp. 78–80. [DOI] [PubMed]
  15. Kokwaro, J. O. (1976). Medicinal Plants of East Africa, p. 45. Nairobi: East African Lit. Bureau.
  16. McCorkindale, N. J., Calzadilla, C. H., Hutchinson, S. A., Kitson, D. H., Ferguson, G. & Campbell, I. M. (1981). Tetrahedron, 37, 649–653.
  17. Nonius (2000). COLLECT Nonius BV, Delft, The Netherlands.
  18. Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307–326. New York: Academic Press.
  19. Rahbaek, L., Christophersen, C., Frisvad, J., Bengaard, H. S., Larsen, S. & Rassing, B. R. (1997). J. Nat. Prod. 60, 811–813.
  20. Rossmann, M. G. & Lipscomb, W. N. (1958). Tetrahedron, 4, 275–293.
  21. Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [DOI] [PubMed]
  22. Wube, A. A., Bucar, F., Gibbons, S. & Asres, K. (2005). Phytochemistry, 66, 2309–2315. [DOI] [PubMed]
  23. Zhang, Y.-X., Jackson, S. H., Rajab, M. S., Fronczek, F. R. & Watkins, S. F. (2006). Acta Cryst. C62, o219–o221. [DOI] [PubMed]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812033636/bt5979sup1.cif

e-68-o2612-sup1.cif (20.1KB, cif)

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812033636/bt5979Isup2.hkl

e-68-o2612-Isup2.hkl (312.2KB, hkl)

Supplementary material file. DOI: 10.1107/S1600536812033636/bt5979Isup3.cml

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

Articles from Acta Crystallographica Section E: Structure Reports Online are provided here courtesy of International Union of Crystallography

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