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Acta Cryst. (2008). E64, o651-o652    [ doi:10.1107/S1600536808004832 ]

1,7-Dihydroxy-2,3,4-trimethoxy-9H-xanthen-9-one monohydrate from Halenia elliptica

P. Yu, X. Shen, C. Hu, E. J. Meehan and L. Chen

Abstract top

The title compound, C16H14O7·H2O, possesses a planar three-ring skeleton; its carbonyl, one of the two hydroxy and two of the three methoxy O atoms and the water molecule form hydrogen bonds, giving rise to a layer structure.

Comment top

Xanthone compounds commonly occur in several higher plant families, such as Gentianaceae,Guttiferae, Moraceae and Polygalaceae. Simple oxygenated xanthones possess different biological activities such as antidepressant, antitumor, antimicrobial, antifungal, anti-inflammatory, antiviral, cardiotonic, hypoglycemic, antihepatotoxic and immunomodulatory (Liou et al., 1993; Basnet et al., 1994; Fernandes et al., 1995; Parmar et al., 1996; Karan et al., 1999; Miura et al., 2001; Pedro et al., 2002; Sousa et al., 2002). The majority of the xanthones isolated so far are hydroxyl or methoxy substituted in the xanthone skeleton. Up to present, only ten simple oxygenated xanthones were characterized by X-ray diffraction (Stout et al., 1969; Vijayalakshmi et al., 1987; Kijjoa et al., 1998; Gales et al., 2001; Kabaleeswaran et al., 2003; Jiang et al., 2004; Shi et al., 2004; Evans et al., 2004; Kato et al., 2005; Shi et al., 2005). 1,7-dihydroxy-2,3,4-trimethoxyxanthone (I) was first isolated from Halenia elliptica D. Don (Gentianaceae) and has antioxidant activity. Its crystal structure is reported for the first time in this paper. The structure of I (Figure 1) is similar to other xanthones reported with a planar three-ring skeleton. The asymmetric unit of crystal I contains one molecule I plus one water molecule. I forms hydrogen bonds with the water molecule through its carbonyl, one of the two hydroxyl and two of the three methoxyl O atoms (Table 1, Figure 2). The crystal structure is stabilized by the extensive hydrogen bond network.

Related literature top

For the antidepressant, antitumor, antimicrobial, antifungal, anti-inflammatory, antiviral, cardiotonic, hypoglycemic, antihepatotoxic and immunomodulatory activities of simple xanthones, see: Basnet et al. (1994); Fernandes et al. (1995); Karan et al. (1999); Liou et al. (1993); Miura et al. (2001); Parmar et al. (1996); Pedro et al. (2002); Sousa et al. (2002). For the crystal structures of oxygenated xanthones, see: Evans et al. (2004); Gales et al. (2001); Jiang et al. (2004); Kabaleeswaran et al. (2003); Kato et al. (2005); Kijjoa et al. (1998); Shi et al. (2004, 2005); Stout et al. (1969); Vijayalakshmi et al. (1987).

Experimental top

Halenia elliptica D. Don was collected in DALI, Yunnan Province, in April 2005 and was identified by Professor Xiaokuang Ma, Department of Pharmacognosy, School of Pharmacy, DALI University, People's Republic of China.

Extraction and isolation: 1,7-dihydroxy-2,3,4-trimethoxyxanthone (I) was isolated from ethyl acetate fraction of the ethanol extract of the aerial parts of Halenia elliptica with other four 1,7-dihydroxy substituted xanthones by silica gel column chromatography with gradient mixtures of petroleum ether and ethyl acetate. Yellow crystals of I were obtained by slow evaporation of a solution in EtOH. M.p.164–165°C. ESI-MS m/z (rel. %): 319[M+H]+.1H-NMR (400 MHz, CDCl3), d12.60 (1H, s, OH-1), 7.60 (1H, d, J=3.0 Hz, H-8), 7.49 (1H, d, J=9.3 Hz, H-5), 7.34 (1H, dd, J=3.0, 9.0 Hz, H-6), 5.32 (1H, br. s, OH-7), 4.15 (3H, s, OCH3), 3.96 (3H, s, OCH3), 3.95 (3H, s, OCH3).

Refinement top

H atoms attached to O atoms were located in a difference map and refined with bond restraints O—H = 0.82 (2) Å. C-bound H atoms were positioned geometrically (C—H 0.93 - 0.96 Å). All H atoms were refined as riding, with Uiso(H) = 1.2 - 1.5 Ueq of the parent atom.

Computing details top

Data collection: SMART (Bruker, 1999); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT (Bruker, 1999); 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).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I). Displacement ellipsoids are drawn at the 50% probability level. Arbitrary atom numbering.
[Figure 2] Fig. 2. The packing of (I), viewed down the b axis.
1,7-dihydroxy-2,3,4-trimethoxy-9H-xanthen-9-one monohydrate top
Crystal data top
C16H14O7·H2OF000 = 704
Mr = 336.29Dx = 1.501 Mg m−3
Monoclinic, P21/cMelting point: 437 K
Hall symbol: -P 2ybcMo Kα radiation
λ = 0.71073 Å
a = 10.9272 (9) ÅCell parameters from 3563 reflections
b = 10.4511 (8) Åθ = 2.5–28.3º
c = 14.0201 (11) ŵ = 0.12 mm−1
β = 111.6830 (10)ºT = 298 K
V = 1487.8 (2) Å3Block, yellow
Z = 40.2 × 0.1 × 0.05 mm
Data collection top
Bruker SMART 1K CCD
diffractometer		2848 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.053
Monochromator: graphiteθmax = 28.3º
T = 298 Kθmin = 2.5º
Thin–slice ω scansh = −14→14
Absorption correction: nonek = −8→13
8808 measured reflectionsl = −18→18
3563 independent reflections
Refinement top
Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH atoms treated by a mixture of
independent and constrained refinement
R[F2 > 2σ(F2)] = 0.046  w = 1/[σ2(Fo2) + (0.0743P)2 + 0.2855P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.142(Δ/σ)max < 0.001
S = 1.06Δρmax = 0.29 e Å−3
3563 reflectionsΔρmin = −0.24 e Å−3
233 parametersExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0085 (18)
Secondary atom site location: difference Fourier map
Crystal data top
C16H14O7·H2OV = 1487.8 (2) Å3
Mr = 336.29Z = 4
Monoclinic, P21/cMo Kα
a = 10.9272 (9) ŵ = 0.12 mm−1
b = 10.4511 (8) ÅT = 298 K
c = 14.0201 (11) Å0.2 × 0.1 × 0.05 mm
β = 111.6830 (10)º
Data collection top
Bruker SMART 1K CCD
diffractometer		3563 independent reflections
Absorption correction: none2848 reflections with I > 2σ(I)
8808 measured reflectionsRint = 0.053
Refinement top
R[F2 > 2σ(F2)] = 0.046233 parameters
wR(F2) = 0.142H atoms treated by a mixture of
independent and constrained refinement
S = 1.06Δρmax = 0.29 e Å−3
3563 reflectionsΔρmin = −0.24 e Å−3
Special details top

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
O50.62447 (9)0.47253 (9)0.17678 (8)0.0374 (2)
O10.44791 (10)0.90069 (10)0.12081 (9)0.0441 (3)
H10.37580.85900.09430.066*
C110.52749 (12)0.68367 (13)0.14635 (9)0.0315 (3)
O60.29738 (10)0.70239 (10)0.06007 (9)0.0492 (3)
O20.69716 (11)0.99477 (10)0.21570 (8)0.0437 (3)
C20.67515 (14)0.86433 (13)0.20640 (10)0.0361 (3)
C120.63679 (13)0.60211 (13)0.18592 (10)0.0325 (3)
C100.39784 (13)0.63185 (13)0.09340 (10)0.0343 (3)
C130.50227 (13)0.41989 (13)0.12579 (10)0.0336 (3)
C40.76454 (13)0.64776 (14)0.23766 (11)0.0370 (3)
C80.26918 (14)0.43164 (14)0.02687 (11)0.0371 (3)
H80.19340.4798−0.00490.045*
O30.89800 (11)0.84290 (12)0.29620 (11)0.0599 (4)
C30.78279 (13)0.78037 (15)0.24786 (11)0.0385 (3)
C90.38925 (13)0.49338 (13)0.08075 (10)0.0331 (3)
C10.54949 (13)0.81769 (13)0.15801 (10)0.0331 (3)
O70.14973 (11)0.23466 (11)−0.03034 (10)0.0517 (3)
H70.08820.2864−0.05600.078*
C70.26315 (14)0.30003 (14)0.02086 (11)0.0386 (3)
O40.86845 (10)0.56302 (11)0.26990 (9)0.0500 (3)
C50.49582 (15)0.28688 (14)0.12202 (11)0.0398 (3)
H50.57110.23830.15430.048*
C60.37723 (16)0.22793 (14)0.07010 (11)0.0421 (3)
H60.37270.13910.06770.051*
C151.02209 (16)0.7842 (2)0.32996 (18)0.0673 (5)
H15A1.03210.73090.38810.101*
H15B1.08950.84860.34920.101*
H15C1.02970.73290.27560.101*
C140.7299 (2)1.04398 (18)0.13328 (16)0.0595 (5)
H14A0.80340.99740.12900.089*
H14B0.75261.13280.14530.089*
H14C0.65571.03490.07000.089*
C160.8790 (2)0.4892 (2)0.35909 (16)0.0701 (6)
H16A0.87950.54570.41320.105*
H16B0.95920.44060.38110.105*
H16C0.80520.43210.34250.105*
O80.92795 (15)0.37653 (18)0.88918 (14)0.0695 (4)
H150.862 (4)0.361 (4)0.905 (3)0.123 (12)*
H160.912 (3)0.436 (3)0.860 (2)0.104 (12)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O50.0319 (5)0.0313 (5)0.0448 (5)0.0041 (4)0.0093 (4)0.0004 (4)
O10.0363 (5)0.0311 (5)0.0567 (6)0.0041 (4)0.0076 (5)0.0031 (4)
C110.0310 (6)0.0309 (6)0.0311 (6)0.0016 (5)0.0098 (5)0.0008 (5)
O60.0318 (5)0.0347 (5)0.0694 (7)0.0041 (4)0.0048 (5)0.0046 (5)
O20.0460 (6)0.0323 (5)0.0512 (6)−0.0056 (4)0.0160 (5)−0.0051 (4)
C20.0382 (7)0.0318 (6)0.0374 (7)−0.0016 (5)0.0128 (6)−0.0024 (5)
C120.0329 (6)0.0314 (6)0.0328 (6)0.0024 (5)0.0116 (5)−0.0001 (5)
C100.0322 (6)0.0318 (6)0.0359 (6)0.0017 (5)0.0089 (5)0.0031 (5)
C130.0348 (7)0.0328 (7)0.0336 (6)0.0019 (5)0.0132 (5)−0.0006 (5)
C40.0297 (6)0.0379 (7)0.0396 (7)0.0051 (5)0.0086 (5)0.0001 (5)
C80.0352 (7)0.0341 (7)0.0393 (7)−0.0005 (5)0.0107 (6)0.0001 (5)
O30.0317 (5)0.0457 (7)0.0854 (9)−0.0031 (5)0.0018 (5)−0.0102 (6)
C30.0318 (6)0.0401 (7)0.0401 (7)−0.0028 (5)0.0091 (5)−0.0042 (6)
C90.0345 (7)0.0314 (6)0.0328 (6)0.0006 (5)0.0119 (5)0.0011 (5)
C10.0342 (6)0.0310 (6)0.0333 (6)0.0024 (5)0.0113 (5)0.0014 (5)
O70.0443 (6)0.0396 (6)0.0659 (7)−0.0102 (5)0.0139 (5)−0.0092 (5)
C70.0422 (7)0.0356 (7)0.0398 (7)−0.0061 (6)0.0175 (6)−0.0047 (6)
O40.0329 (5)0.0435 (6)0.0661 (7)0.0095 (4)0.0095 (5)0.0028 (5)
C50.0433 (7)0.0315 (7)0.0449 (7)0.0061 (6)0.0166 (6)0.0003 (6)
C60.0519 (8)0.0294 (6)0.0483 (8)−0.0010 (6)0.0222 (7)−0.0033 (6)
C150.0329 (8)0.0638 (12)0.0911 (14)−0.0019 (8)0.0063 (8)−0.0113 (10)
C140.0677 (11)0.0416 (9)0.0790 (12)−0.0009 (8)0.0387 (10)0.0066 (8)
C160.0575 (11)0.0644 (12)0.0714 (12)0.0185 (9)0.0038 (9)0.0198 (10)
O80.0527 (8)0.0662 (10)0.0874 (11)0.0122 (7)0.0232 (7)0.0162 (8)
Geometric parameters (Å, °) top
O5—C121.3623 (16)O3—C31.3567 (17)
O5—C131.3753 (17)O3—C151.402 (2)
O1—C11.3523 (16)O7—C71.3640 (17)
O1—H10.8561O7—H70.8336
C11—C121.4040 (18)C7—C61.401 (2)
C11—C11.4204 (19)O4—C161.437 (2)
C11—C101.4402 (18)C5—C61.375 (2)
O6—C101.2601 (16)C5—H50.9300
O2—C21.3820 (17)C6—H60.9300
O2—C141.426 (2)C15—H15A0.9600
C2—C11.3765 (19)C15—H15B0.9600
C2—C31.409 (2)C15—H15C0.9600
C12—C41.3979 (19)C14—H14A0.9600
C10—C91.4568 (19)C14—H14B0.9600
C13—C51.3919 (19)C14—H14C0.9600
C13—C91.3920 (19)C16—H16A0.9600
C4—O41.3779 (16)C16—H16B0.9600
C4—C31.400 (2)C16—H16C0.9600
C8—C71.3781 (19)O8—H150.85 (4)
C8—C91.4057 (19)O8—H160.73 (4)
C8—H80.9300
C12—O5—C13119.33 (10)O1—C1—C11120.54 (12)
C1—O1—H1109.5C2—C1—C11120.10 (12)
C12—C11—C1118.04 (12)C7—O7—H7109.5
C12—C11—C10120.44 (12)O7—C7—C8123.07 (14)
C1—C11—C10121.51 (12)O7—C7—C6117.39 (13)
C2—O2—C14111.49 (12)C8—C7—C6119.54 (13)
C1—C2—O2120.20 (12)C4—O4—C16114.94 (13)
C1—C2—C3120.75 (13)C6—C5—C13119.48 (14)
O2—C2—C3119.05 (12)C6—C5—H5120.3
O5—C12—C4115.67 (12)C13—C5—H5120.3
O5—C12—C11121.75 (12)C5—C6—C7120.84 (13)
C4—C12—C11122.58 (13)C5—C6—H6119.6
O6—C10—C11121.83 (12)C7—C6—H6119.6
O6—C10—C9121.87 (12)O3—C15—H15A109.5
C11—C10—C9116.31 (12)O3—C15—H15B109.5
O5—C13—C5116.43 (12)H15A—C15—H15B109.5
O5—C13—C9122.92 (12)O3—C15—H15C109.5
C5—C13—C9120.65 (13)H15A—C15—H15C109.5
O4—C4—C12119.65 (13)H15B—C15—H15C109.5
O4—C4—C3122.26 (12)O2—C14—H14A109.5
C12—C4—C3117.91 (12)O2—C14—H14B109.5
C7—C8—C9120.33 (13)H14A—C14—H14B109.5
C7—C8—H8119.8O2—C14—H14C109.5
C9—C8—H8119.8H14A—C14—H14C109.5
C3—O3—C15124.13 (14)H14B—C14—H14C109.5
O3—C3—C4126.78 (13)O4—C16—H16A109.5
O3—C3—C2112.65 (13)O4—C16—H16B109.5
C4—C3—C2120.57 (12)H16A—C16—H16B109.5
C13—C9—C8119.08 (12)O4—C16—H16C109.5
C13—C9—C10119.11 (12)H16A—C16—H16C109.5
C8—C9—C10121.79 (12)H16B—C16—H16C109.5
O1—C1—C2119.35 (12)H15—O8—H16106 (3)
C14—O2—C2—C1−93.37 (16)O5—C13—C9—C8177.67 (12)
C14—O2—C2—C387.18 (17)C5—C13—C9—C8−3.1 (2)
C13—O5—C12—C4−179.21 (11)O5—C13—C9—C10−4.2 (2)
C13—O5—C12—C111.25 (19)C5—C13—C9—C10175.03 (12)
C1—C11—C12—O5−179.12 (11)C7—C8—C9—C131.5 (2)
C10—C11—C12—O5−0.6 (2)C7—C8—C9—C10−176.60 (13)
C1—C11—C12—C41.4 (2)O6—C10—C9—C13−175.33 (13)
C10—C11—C12—C4179.86 (12)C11—C10—C9—C134.52 (19)
C12—C11—C10—O6177.61 (13)O6—C10—C9—C82.7 (2)
C1—C11—C10—O6−4.0 (2)C11—C10—C9—C8−177.40 (12)
C12—C11—C10—C9−2.24 (18)O2—C2—C1—O1−0.8 (2)
C1—C11—C10—C9176.19 (12)C3—C2—C1—O1178.70 (12)
C12—O5—C13—C5−178.02 (12)O2—C2—C1—C11178.48 (12)
C12—O5—C13—C91.24 (19)C3—C2—C1—C11−2.1 (2)
O5—C12—C4—O43.85 (19)C12—C11—C1—O1179.59 (11)
C11—C12—C4—O4−176.61 (12)C10—C11—C1—O11.1 (2)
O5—C12—C4—C3179.11 (12)C12—C11—C1—C20.37 (19)
C11—C12—C4—C3−1.4 (2)C10—C11—C1—C2−178.10 (12)
C15—O3—C3—C410.8 (3)C9—C8—C7—O7−179.92 (13)
C15—O3—C3—C2−169.68 (17)C9—C8—C7—C60.9 (2)
O4—C4—C3—O3−5.7 (2)C12—C4—O4—C16−75.54 (18)
C12—C4—C3—O3179.12 (14)C3—C4—O4—C16109.41 (18)
O4—C4—C3—C2174.75 (13)O5—C13—C5—C6−178.43 (12)
C12—C4—C3—C2−0.4 (2)C9—C13—C5—C62.3 (2)
C1—C2—C3—O3−177.47 (13)C13—C5—C6—C70.2 (2)
O2—C2—C3—O31.98 (19)O7—C7—C6—C5179.03 (13)
C1—C2—C3—C42.1 (2)C8—C7—C6—C5−1.8 (2)
O2—C2—C3—C4−178.45 (12)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O8i—H16i···O20.73 (3)2.58 (3)3.091 (2)129.4
O8i—H16i···O30.73 (3)2.46 (3)3.177 (2)167.3
O8ii—H15ii···O60.84 (5)2.08 (5)2.923 (2)172.3
O7—H7···O8iii0.831.882.706 (2)169
Symmetry codes: (i) x, −y+3/2, z−1/2; (ii) −x+1, −y+1, −z+1; (iii) x−1, y, z−1.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O8i—H16i···O20.73 (3)2.58 (3)3.091 (2)129.4
O8i—H16i···O30.73 (3)2.46 (3)3.177 (2)167.3
O8ii—H15ii···O60.84 (5)2.08 (5)2.923 (2)172.3
O7—H7···O8iii0.831.882.706 (2)169
Symmetry codes: (i) x, −y+3/2, z−1/2; (ii) −x+1, −y+1, −z+1; (iii) x−1, y, z−1.
Acknowledgements top

This work was supported in part by the NSF-EPSCoR, USA.

references
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