organic compounds
6,8-Dihydroxy-8a-methyl-3,5-dimethylidenedecahydronaphtho[2,3-b]furan-2(3H)-one
aCollege of Life and Environment Science, Minzu University of China, Beijing 100081, People's Republic of China
*Correspondence e-mail: wangws@muc.edu.cn
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 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
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Data collection
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Refinement
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Data collection: CrystalClear (Rigaku/MSC, 2008); cell 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.
Supporting information
10.1107/S160053681204425X/rk2376sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S160053681204425X/rk2376Isup2.hkl
Supporting information file. DOI: 10.1107/S160053681204425X/rk2376Isup3.cml
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.
The hydrogen atoms which bonded with C were placed in calculated positions with C–H = 0.95-1.00Å. The hydroxyl H atoms were located in Fourier difference map. The H atoms in these droups are splitted with s.o.f. = 0.5. The positions of hydroxyl H atoms were refined freely. All H atoms were refined with Uiso(H) = 1.2Ueq(C, O).
Data collection: CrystalClear (Rigaku/MSC, 2008); cell
CrystalClear (Rigaku/MSC, 2008); data reduction: CrystalClear (Rigaku/MSC, 2008); 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 (Sheldrick, 2008).C15H20O4 | Dx = 1.342 Mg m−3 |
Mr = 264.31 | Mo Kα radiation, λ = 0.71073 Å |
Tetragonal, P41212 | Cell parameters from 4658 reflections |
Hall symbol: P 4abw 2nw | θ = 3.2–27.9° |
a = 6.4737 (4) Å | µ = 0.10 mm−1 |
c = 62.438 (8) Å | T = 133 K |
V = 2616.7 (5) Å3 | Block, colourless |
Z = 8 | 0.54 × 0.48 × 0.32 mm |
F(000) = 1136 |
Rigaku AFC10/Saturn-724+ CCD diffractometer | 1826 reflections with I > 2σ(I) |
Radiation source: Rotating Anode | Rint = 0.058 |
Graphite monochromator | θmax = 27.9°, θmin = 2.6° |
Detector resolution: 28.5714 pixels mm-1 | h = −8→8 |
ϕ– and ω–scans | k = −8→8 |
19607 measured reflections | l = −82→82 |
1990 independent reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.047 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.124 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.00 | w = 1/[σ2(Fo2) + (0.0836P)2 + 0.316P] where P = (Fo2 + 2Fc2)/3 |
1990 reflections | (Δ/σ)max = 0.001 |
185 parameters | Δρmax = 0.23 e Å−3 |
6 restraints | Δρmin = −0.21 e Å−3 |
C15H20O4 | Z = 8 |
Mr = 264.31 | Mo Kα radiation |
Tetragonal, P41212 | µ = 0.10 mm−1 |
a = 6.4737 (4) Å | T = 133 K |
c = 62.438 (8) Å | 0.54 × 0.48 × 0.32 mm |
V = 2616.7 (5) Å3 |
Rigaku AFC10/Saturn-724+ CCD diffractometer | 1826 reflections with I > 2σ(I) |
19607 measured reflections | Rint = 0.058 |
1990 independent reflections |
R[F2 > 2σ(F2)] = 0.047 | 6 restraints |
wR(F2) = 0.124 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.00 | Δρmax = 0.23 e Å−3 |
1990 reflections | Δρmin = −0.21 e Å−3 |
185 parameters |
Experimental. Since the skeleton methyl groups in eudesmanolide are biogenic 8a position, we draw the relative stereochemistry of the title eudesmanolide, by reference to the structures of related eudesmanolide in (Masao & Fumiko, 1975) although the absolute configuration could not be reliably determined from anomalous dispersion effects, if Mo radiation is used in experiment. Furthermore, the relative stereochemistry in the title compound was confirmed by NMR data. 13C NMR (125 MHz, CDCl3, δ,p.p.m.): 178.1 (C12), 149.2 (C4), 141.4 (C11), 120.5 (C13), 110.9 (C15), 77.6 (C8), 75.2 (C3), 74.7 (C1), 63.8 (C10), 40.3 (C7), 33.9 (C5), 33.6 (C9), 33.5 (C2), 26.8 (C6), 17.7 (C14). |
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 | Occ. (<1) | |
O1 | 0.6749 (2) | 0.7974 (2) | 0.09621 (2) | 0.0238 (3) | |
O2 | 0.9609 (2) | 0.7729 (3) | 0.01700 (2) | 0.0259 (4) | |
H2O | 0.903 (5) | 0.820 (6) | 0.0061 (5) | 0.031* | 0.50 |
H2O' | 1.080 (3) | 0.727 (4) | 0.0149 (8) | 0.031* | 0.50 |
O3 | 1.2633 (3) | 0.4894 (3) | 0.01385 (3) | 0.0277 (4) | |
H3O | 1.329 (7) | 0.432 (8) | 0.0040 (7) | 0.033* | 0.50 |
H3O' | 1.216 (8) | 0.609 (4) | 0.0132 (9) | 0.033* | 0.50 |
O4 | 0.6433 (3) | 0.7218 (3) | 0.13102 (3) | 0.0289 (4) | |
C1 | 0.8323 (3) | 0.6114 (3) | 0.02599 (3) | 0.0222 (4) | |
H1 | 0.6856 | 0.6382 | 0.0218 | 0.027* | |
C2 | 0.8995 (3) | 0.4040 (4) | 0.01641 (3) | 0.0252 (5) | |
H2A | 0.8023 | 0.2947 | 0.0210 | 0.030* | |
H2B | 0.8947 | 0.4124 | 0.0006 | 0.030* | |
C3 | 1.1183 (3) | 0.3474 (3) | 0.02353 (3) | 0.0230 (4) | |
H3 | 1.1504 | 0.2041 | 0.0186 | 0.028* | |
C4 | 1.1394 (3) | 0.3561 (3) | 0.04749 (3) | 0.0188 (4) | |
C5 | 1.0717 (3) | 0.5576 (3) | 0.05753 (3) | 0.0176 (4) | |
H5 | 1.1636 | 0.6681 | 0.0517 | 0.021* | |
C6 | 1.0932 (3) | 0.5634 (3) | 0.08181 (3) | 0.0197 (4) | |
H6A | 1.2369 | 0.5273 | 0.0857 | 0.024* | |
H6B | 1.0010 | 0.4578 | 0.0881 | 0.024* | |
C7 | 1.0399 (3) | 0.7753 (3) | 0.09141 (3) | 0.0199 (4) | |
H7 | 1.1590 | 0.8724 | 0.0898 | 0.024* | |
C8 | 0.8417 (3) | 0.8722 (3) | 0.08222 (3) | 0.0206 (4) | |
H8 | 0.8518 | 1.0254 | 0.0840 | 0.025* | |
C9 | 0.7925 (3) | 0.8280 (3) | 0.05891 (3) | 0.0208 (4) | |
H9A | 0.8663 | 0.9307 | 0.0500 | 0.025* | |
H9B | 0.6427 | 0.8502 | 0.0567 | 0.025* | |
C10 | 0.8472 (3) | 0.6116 (3) | 0.05061 (3) | 0.0196 (4) | |
C11 | 0.9826 (3) | 0.7535 (3) | 0.11464 (3) | 0.0221 (4) | |
C12 | 0.7532 (3) | 0.7548 (3) | 0.11580 (3) | 0.0217 (4) | |
C13 | 1.1009 (4) | 0.7239 (4) | 0.13160 (3) | 0.0287 (5) | |
H13A | 1.0399 | 0.7022 | 0.1453 | 0.034* | |
H13B | 1.2470 | 0.7243 | 0.1301 | 0.034* | |
C14 | 0.6907 (3) | 0.4523 (3) | 0.05931 (4) | 0.0235 (5) | |
H14A | 0.6728 | 0.4728 | 0.0747 | 0.028* | |
H14B | 0.7424 | 0.3124 | 0.0566 | 0.028* | |
H14C | 0.5577 | 0.4707 | 0.0521 | 0.028* | |
C15 | 1.2136 (3) | 0.1949 (3) | 0.05820 (4) | 0.0253 (5) | |
H15A | 1.2536 | 0.0735 | 0.0507 | 0.030* | |
H15B | 1.2267 | 0.2010 | 0.0733 | 0.030* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0227 (8) | 0.0298 (8) | 0.0189 (7) | 0.0009 (6) | 0.0021 (6) | 0.0013 (6) |
O2 | 0.0313 (9) | 0.0272 (8) | 0.0192 (8) | −0.0013 (7) | 0.0007 (6) | 0.0057 (6) |
O3 | 0.0311 (9) | 0.0287 (8) | 0.0232 (8) | −0.0024 (7) | 0.0085 (7) | 0.0027 (7) |
O4 | 0.0321 (9) | 0.0319 (8) | 0.0228 (8) | 0.0021 (7) | 0.0073 (7) | 0.0024 (7) |
C1 | 0.0221 (10) | 0.0250 (10) | 0.0196 (10) | −0.0023 (8) | −0.0023 (8) | 0.0024 (8) |
C2 | 0.0281 (11) | 0.0314 (12) | 0.0161 (10) | −0.0054 (9) | −0.0024 (8) | −0.0028 (9) |
C3 | 0.0272 (11) | 0.0210 (10) | 0.0208 (10) | −0.0026 (8) | 0.0038 (9) | −0.0021 (8) |
C4 | 0.0183 (9) | 0.0207 (9) | 0.0173 (10) | −0.0031 (7) | 0.0014 (8) | −0.0015 (8) |
C5 | 0.0182 (9) | 0.0187 (10) | 0.0158 (9) | −0.0015 (7) | −0.0012 (7) | −0.0003 (8) |
C6 | 0.0215 (10) | 0.0211 (10) | 0.0164 (9) | 0.0004 (8) | −0.0008 (8) | 0.0014 (8) |
C7 | 0.0213 (10) | 0.0212 (10) | 0.0171 (9) | −0.0017 (8) | −0.0012 (8) | 0.0010 (8) |
C8 | 0.0241 (10) | 0.0198 (9) | 0.0178 (10) | −0.0008 (8) | 0.0015 (8) | 0.0009 (8) |
C9 | 0.0222 (10) | 0.0212 (10) | 0.0190 (10) | 0.0024 (8) | −0.0002 (8) | 0.0025 (8) |
C10 | 0.0183 (9) | 0.0234 (10) | 0.0169 (10) | −0.0012 (8) | −0.0011 (8) | 0.0017 (8) |
C11 | 0.0265 (10) | 0.0202 (10) | 0.0197 (10) | −0.0004 (8) | 0.0014 (8) | −0.0010 (8) |
C12 | 0.0282 (11) | 0.0201 (10) | 0.0169 (9) | 0.0007 (8) | 0.0015 (8) | −0.0007 (8) |
C13 | 0.0318 (12) | 0.0360 (12) | 0.0182 (10) | −0.0009 (10) | −0.0014 (9) | 0.0003 (9) |
C14 | 0.0203 (10) | 0.0257 (11) | 0.0245 (10) | −0.0056 (8) | 0.0015 (8) | 0.0005 (9) |
C15 | 0.0256 (10) | 0.0246 (11) | 0.0255 (11) | −0.0009 (8) | 0.0008 (9) | −0.0012 (8) |
O1—C12 | 1.353 (3) | C6—C7 | 1.536 (3) |
O1—C8 | 1.471 (2) | C6—H6A | 0.9900 |
O2—C1 | 1.449 (3) | C6—H6B | 0.9900 |
O2—H2O | 0.840 (10) | C7—C11 | 1.504 (3) |
O2—H2O' | 0.839 (10) | C7—C8 | 1.539 (3) |
O3—C3 | 1.447 (3) | C7—H7 | 1.0000 |
O3—H3O | 0.834 (10) | C8—C9 | 1.517 (3) |
O3—H3O' | 0.836 (10) | C8—H8 | 1.0000 |
O4—C12 | 1.206 (3) | C9—C10 | 1.535 (3) |
C1—C2 | 1.533 (3) | C9—H9A | 0.9900 |
C1—C10 | 1.540 (3) | C9—H9B | 0.9900 |
C1—H1 | 1.0000 | C10—C14 | 1.544 (3) |
C2—C3 | 1.529 (3) | C11—C13 | 1.321 (3) |
C2—H2A | 0.9900 | C11—C12 | 1.486 (3) |
C2—H2B | 0.9900 | C13—H13A | 0.9500 |
C3—C4 | 1.503 (3) | C13—H13B | 0.9500 |
C3—H3 | 1.0000 | C14—H14A | 0.9800 |
C4—C15 | 1.330 (3) | C14—H14B | 0.9800 |
C4—C5 | 1.512 (3) | C14—H14C | 0.9800 |
C5—C6 | 1.523 (3) | C15—H15A | 0.9500 |
C5—C10 | 1.556 (3) | C15—H15B | 0.9500 |
C5—H5 | 1.0000 | ||
C12—O1—C8 | 109.21 (16) | C11—C7—C8 | 101.06 (17) |
C1—O2—H2O | 108.7 (12) | C6—C7—C8 | 113.93 (16) |
C1—O2—H2O' | 109.6 (12) | C11—C7—H7 | 110.4 |
H2O—O2—H2O' | 115 (5) | C6—C7—H7 | 110.4 |
C3—O3—H3O | 111 (4) | C8—C7—H7 | 110.4 |
C3—O3—H3O' | 112 (4) | O1—C8—C9 | 110.70 (17) |
H3O—O3—H3O' | 124 (6) | O1—C8—C7 | 104.87 (15) |
O2—C1—C2 | 108.53 (17) | C9—C8—C7 | 117.13 (17) |
O2—C1—C10 | 110.48 (16) | O1—C8—H8 | 107.9 |
C2—C1—C10 | 111.86 (17) | C9—C8—H8 | 107.9 |
O2—C1—H1 | 108.6 | C7—C8—H8 | 107.9 |
C2—C1—H1 | 108.6 | C8—C9—C10 | 116.56 (16) |
C10—C1—H1 | 108.6 | C8—C9—H9A | 108.2 |
C3—C2—C1 | 111.05 (17) | C10—C9—H9A | 108.2 |
C3—C2—H2A | 109.4 | C8—C9—H9B | 108.2 |
C1—C2—H2A | 109.4 | C10—C9—H9B | 108.2 |
C3—C2—H2B | 109.4 | H9A—C9—H9B | 107.3 |
C1—C2—H2B | 109.4 | C9—C10—C1 | 108.84 (16) |
H2A—C2—H2B | 108.0 | C9—C10—C14 | 109.84 (17) |
O3—C3—C4 | 109.47 (17) | C1—C10—C14 | 108.02 (16) |
O3—C3—C2 | 109.10 (17) | C9—C10—C5 | 109.08 (16) |
C4—C3—C2 | 111.38 (17) | C1—C10—C5 | 109.60 (16) |
O3—C3—H3 | 108.9 | C14—C10—C5 | 111.41 (17) |
C4—C3—H3 | 108.9 | C13—C11—C12 | 122.7 (2) |
C2—C3—H3 | 108.9 | C13—C11—C7 | 130.1 (2) |
C15—C4—C3 | 120.26 (19) | C12—C11—C7 | 107.06 (18) |
C15—C4—C5 | 124.99 (19) | O4—C12—O1 | 121.8 (2) |
C3—C4—C5 | 114.75 (17) | O4—C12—C11 | 128.8 (2) |
C4—C5—C6 | 114.06 (17) | O1—C12—C11 | 109.35 (17) |
C4—C5—C10 | 110.44 (16) | C11—C13—H13A | 120.0 |
C6—C5—C10 | 110.86 (16) | C11—C13—H13B | 120.0 |
C4—C5—H5 | 107.0 | H13A—C13—H13B | 120.0 |
C6—C5—H5 | 107.0 | C10—C14—H14A | 109.5 |
C10—C5—H5 | 107.0 | C10—C14—H14B | 109.5 |
C5—C6—C7 | 112.94 (16) | H14A—C14—H14B | 109.5 |
C5—C6—H6A | 109.0 | C10—C14—H14C | 109.5 |
C7—C6—H6A | 109.0 | H14A—C14—H14C | 109.5 |
C5—C6—H6B | 109.0 | H14B—C14—H14C | 109.5 |
C7—C6—H6B | 109.0 | C4—C15—H15A | 120.0 |
H6A—C6—H6B | 107.8 | C4—C15—H15B | 120.0 |
C11—C7—C6 | 110.34 (17) | H15A—C15—H15B | 120.0 |
O2—C1—C2—C3 | 65.9 (2) | C8—C9—C10—C14 | 74.5 (2) |
C10—C1—C2—C3 | −56.2 (2) | C8—C9—C10—C5 | −47.9 (2) |
C1—C2—C3—O3 | −68.2 (2) | O2—C1—C10—C9 | 55.0 (2) |
C1—C2—C3—C4 | 52.7 (2) | C2—C1—C10—C9 | 176.05 (17) |
O3—C3—C4—C15 | −112.1 (2) | O2—C1—C10—C14 | 174.25 (17) |
C2—C3—C4—C15 | 127.1 (2) | C2—C1—C10—C14 | −64.7 (2) |
O3—C3—C4—C5 | 67.6 (2) | O2—C1—C10—C5 | −64.2 (2) |
C2—C3—C4—C5 | −53.2 (2) | C2—C1—C10—C5 | 56.8 (2) |
C15—C4—C5—C6 | −0.6 (3) | C4—C5—C10—C9 | −173.51 (16) |
C3—C4—C5—C6 | 179.74 (17) | C6—C5—C10—C9 | 59.1 (2) |
C15—C4—C5—C10 | −126.2 (2) | C4—C5—C10—C1 | −54.4 (2) |
C3—C4—C5—C10 | 54.1 (2) | C6—C5—C10—C1 | 178.14 (16) |
C4—C5—C6—C7 | 175.41 (16) | C4—C5—C10—C14 | 65.1 (2) |
C10—C5—C6—C7 | −59.2 (2) | C6—C5—C10—C14 | −62.4 (2) |
C5—C6—C7—C11 | 157.85 (17) | C6—C7—C11—C13 | 76.2 (3) |
C5—C6—C7—C8 | 45.0 (2) | C8—C7—C11—C13 | −162.9 (2) |
C12—O1—C8—C9 | 153.66 (17) | C6—C7—C11—C12 | −99.4 (2) |
C12—O1—C8—C7 | 26.4 (2) | C8—C7—C11—C12 | 21.5 (2) |
C11—C7—C8—O1 | −28.42 (19) | C8—O1—C12—O4 | 168.33 (19) |
C6—C7—C8—O1 | 89.89 (19) | C8—O1—C12—C11 | −12.6 (2) |
C11—C7—C8—C9 | −151.58 (17) | C13—C11—C12—O4 | −3.7 (4) |
C6—C7—C8—C9 | −33.3 (2) | C7—C11—C12—O4 | 172.3 (2) |
O1—C8—C9—C10 | −83.9 (2) | C13—C11—C12—O1 | 177.4 (2) |
C7—C8—C9—C10 | 36.2 (3) | C7—C11—C12—O1 | −6.6 (2) |
C8—C9—C10—C1 | −167.46 (17) |
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) |
Symmetry codes: (i) y, x, −z; (ii) y+1, x−1, −z. |
Experimental details
Crystal data | |
Chemical formula | C15H20O4 |
Mr | 264.31 |
Crystal system, space group | Tetragonal, P41212 |
Temperature (K) | 133 |
a, c (Å) | 6.4737 (4), 62.438 (8) |
V (Å3) | 2616.7 (5) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 0.10 |
Crystal size (mm) | 0.54 × 0.48 × 0.32 |
Data collection | |
Diffractometer | Rigaku AFC10/Saturn-724+ CCD diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 19607, 1990, 1826 |
Rint | 0.058 |
(sin θ/λ)max (Å−1) | 0.658 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.047, 0.124, 1.00 |
No. of reflections | 1990 |
No. of parameters | 185 |
No. of restraints | 6 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.23, −0.21 |
Computer programs: CrystalClear (Rigaku/MSC, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2O···O2i | 0.840 (10) | 1.898 (12) | 2.733 (3) | 173 (5) |
O2—H2O'···O3 | 0.839 (10) | 1.942 (17) | 2.690 (2) | 147.9 (17) |
O3—H3O'···O2 | 0.836 (10) | 1.97 (4) | 2.690 (2) | 143 (5) |
O3—H3O···O3ii | 0.834 (10) | 1.876 (16) | 2.697 (3) | 168 (6) |
Symmetry codes: (i) y, x, −z; (ii) y+1, x−1, −z. |
Acknowledgements
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.
References
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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].