organic compounds
5-Hydroxy-3,4′,6,7-tetramethoxyflavone
aGuangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine and New Drugs Research, Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, Guangzhou 510632, People's Republic of China
*Correspondence e-mail: tliyl@jnu.edu.cn
The title compound, C19H18O7 [systematic name 5-hydroxy-3,6,7-trimethoxy-2-(4-methoxyphenyl)-4H-1-benzopyran-4-one], is a flavonoid which was isolated from the traditional Chinese medicine Laggera alata. The benzene ring of the benzopyranone unit forms dihedral angles of 1.72 (3) and 37.39 (5)° with the pyran ring and the substituent benzene ring, respectively. The molecular conformation is stabilized by an intramolecular phenol O—H⋯Oketone hydrogen bond.
Related literature
For general background to the synthesis and isolation of the title compound, see: Goldsworthy & Robert (1936); Sy & Brown (1998); Yang et al. (2007); Masateru et al. (2009). For its anti-hepatotoxic activity, see: Chhaya & Mishra (2007).
Experimental
Crystal data
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Refinement
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Data collection: CrysAlis PRO (Agilent, 2011); cell CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); 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
https://doi.org/10.1107/S160053681103827X/zs2143sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S160053681103827X/zs2143Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S160053681103827X/zs2143Isup3.cml
The title compound was isolated from the herbs of the traditional Chinese medicine Laggera alata. The herbs of Laggera alata (5 kg) was extracted with 95% ethanol at room temperature and the extracted solution was concentrated by rotary evaporator. The crude extract was suspended in distilled water and partitioned with petroleum ether, ethyl acetate and n-butanol. The title compound (50 mg) was isolated from the petroleum ether fraction using silica gel
and crystals were obtained after slow evaporation of an ethyl acetate solution at room temperature.The C-bound H atoms were positioned geometrically and were included in the
in the riding-model approximation, with C—H = 0.96 Å (CH3) ,0.93 Å (aryl H) and O—H = 0.82 Å and with Uiso(H) = 1.2Ueq(C) (aryl H) and = 1.5Ueq[C(methyl) and O].The title compound, the flavonoid C19H18O7 [systematic name 5-hydroxy-3,6,7-trimethoxy-2-(4-methoxyphenyl)-4H-1-benzopyran-4-one], (Fig. 1) was originally sythesised from trimethoxyacetophenone (Goldsworthy & Robert, 1936). It was also isolated from Artemisia annua (Sy & Brown, 1998), Laggera pterodonta (Yang et al., 2007) and Aites agnus-castus (Masateru et al., 2009). The flavonoid was also proved to possess significant anti-hepatotoxic activity (Chhaya et al., 2007). The present compound was isolated from the traditional Chinese medicine Laggera alata. In the
the dihedral angle between the plane of the benzene ring A and the pyran plane C is 1.72 (3)°, while that between the benzene ring A and the phenyl ring B is 37.39 (5)°. The is stabilized by an intramolecular phenol O—H···Oketone hydrogen-bonding interaction (Table 1).For general background to the synthesis and isolation of the title compound, see: Goldsworthy & Robert (1936); Sy & Brown (1998); Yang et al. (2007); Masateru et al. (2009). For its anti-hepatotoxic activity, see: Chhaya & Mishra (2007).
Data collection: CrysAlis PRO (Agilent, 2011); cell
CrysAlis PRO (Agilent, 2011); data reduction: CrysAlis PRO (Agilent, 2011); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); 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 50% probability displacement ellipsoids and the atom-numbering scheme. |
C19H18O7 | F(000) = 752 |
Mr = 358.33 | Dx = 1.391 Mg m−3 |
Monoclinic, P21/c | Cu Kα radiation, λ = 1.5418 Å |
a = 16.6029 (3) Å | Cell parameters from 3031 reflections |
b = 7.40255 (12) Å | θ = 3.2–62.6° |
c = 14.8666 (3) Å | µ = 0.90 mm−1 |
β = 110.487 (2)° | T = 295 K |
V = 1711.60 (6) Å3 | Block, colourless |
Z = 4 | 0.26 × 0.21 × 0.18 mm |
Oxford Diffraction Xcalibur Sapphire3 Gemini Ultra CCD diffractometer | 2681 independent reflections |
Radiation source: Enhance Ultra (Cu) X-ray Source | 2380 reflections with I > 2σ(I) |
Mirror monochromator | Rint = 0.016 |
Detector resolution: 16.0288 pixels mm-1 | θmax = 62.7°, θmin = 5.7° |
ω scans | h = −19→18 |
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011) | k = −8→8 |
Tmin = 0.596, Tmax = 1.000 | l = −12→17 |
5568 measured 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)] = 0.035 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.097 | H-atom parameters constrained |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0545P)2 + 0.2624P] where P = (Fo2 + 2Fc2)/3 |
2681 reflections | (Δ/σ)max = 0.001 |
241 parameters | Δρmax = 0.14 e Å−3 |
0 restraints | Δρmin = −0.13 e Å−3 |
C19H18O7 | V = 1711.60 (6) Å3 |
Mr = 358.33 | Z = 4 |
Monoclinic, P21/c | Cu Kα radiation |
a = 16.6029 (3) Å | µ = 0.90 mm−1 |
b = 7.40255 (12) Å | T = 295 K |
c = 14.8666 (3) Å | 0.26 × 0.21 × 0.18 mm |
β = 110.487 (2)° |
Oxford Diffraction Xcalibur Sapphire3 Gemini Ultra CCD diffractometer | 2681 independent reflections |
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2011) | 2380 reflections with I > 2σ(I) |
Tmin = 0.596, Tmax = 1.000 | Rint = 0.016 |
5568 measured reflections |
R[F2 > 2σ(F2)] = 0.035 | 0 restraints |
wR(F2) = 0.097 | H-atom parameters constrained |
S = 1.03 | Δρmax = 0.14 e Å−3 |
2681 reflections | Δρmin = −0.13 e Å−3 |
241 parameters |
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 | ||
C1 | 0.48173 (9) | 0.62713 (18) | 0.35189 (9) | 0.0426 (3) | |
H1 | 0.4827 | 0.6247 | 0.4148 | 0.051* | |
C2 | 0.55652 (9) | 0.65137 (18) | 0.33208 (9) | 0.0426 (3) | |
C3 | 0.55508 (9) | 0.65911 (18) | 0.23692 (10) | 0.0437 (3) | |
C4 | 0.47856 (10) | 0.63752 (18) | 0.16217 (9) | 0.0452 (4) | |
C5 | 0.40106 (9) | 0.60851 (18) | 0.18019 (9) | 0.0425 (3) | |
C6 | 0.40584 (9) | 0.60677 (17) | 0.27555 (9) | 0.0400 (3) | |
C7 | 0.31987 (10) | 0.58282 (19) | 0.10407 (10) | 0.0470 (4) | |
C8 | 0.24726 (9) | 0.55273 (19) | 0.13451 (10) | 0.0463 (4) | |
C9 | 0.25552 (9) | 0.55542 (18) | 0.22864 (9) | 0.0426 (3) | |
C10 | 0.18754 (9) | 0.54065 (19) | 0.27030 (9) | 0.0438 (3) | |
C11 | 0.19372 (9) | 0.6426 (2) | 0.35134 (10) | 0.0471 (4) | |
H11 | 0.2413 | 0.7167 | 0.3786 | 0.057* | |
C12 | 0.13104 (9) | 0.6358 (2) | 0.39175 (10) | 0.0512 (4) | |
H12 | 0.1363 | 0.7058 | 0.4455 | 0.061* | |
C13 | 0.05974 (9) | 0.5249 (2) | 0.35272 (10) | 0.0502 (4) | |
C14 | 0.05317 (10) | 0.4198 (2) | 0.27362 (12) | 0.0581 (4) | |
H14 | 0.0063 | 0.3432 | 0.2478 | 0.070* | |
C15 | 0.11659 (10) | 0.4286 (2) | 0.23276 (11) | 0.0553 (4) | |
H15 | 0.1114 | 0.3581 | 0.1792 | 0.066* | |
C16 | 0.64117 (10) | 0.6460 (3) | 0.49839 (11) | 0.0672 (5) | |
H16A | 0.6228 | 0.5260 | 0.5065 | 0.101* | |
H16B | 0.6050 | 0.7324 | 0.5140 | 0.101* | |
H16C | 0.6996 | 0.6630 | 0.5402 | 0.101* | |
C17 | 0.67982 (12) | 0.5470 (3) | 0.21626 (15) | 0.0744 (5) | |
H17A | 0.6467 | 0.4644 | 0.1676 | 0.112* | |
H17B | 0.6983 | 0.4879 | 0.2776 | 0.112* | |
H17C | 0.7292 | 0.5860 | 0.2020 | 0.112* | |
C18 | 0.15121 (13) | 0.3816 (3) | 0.00626 (14) | 0.0818 (6) | |
H18A | 0.1759 | 0.4002 | −0.0425 | 0.123* | |
H18B | 0.0905 | 0.3617 | −0.0234 | 0.123* | |
H18C | 0.1773 | 0.2782 | 0.0442 | 0.123* | |
C19 | −0.07302 (12) | 0.4180 (3) | 0.36159 (15) | 0.0807 (6) | |
H19A | −0.1054 | 0.4487 | 0.2961 | 0.121* | |
H19B | −0.1084 | 0.4341 | 0.4001 | 0.121* | |
H19C | −0.0549 | 0.2942 | 0.3650 | 0.121* | |
O1 | 0.33340 (6) | 0.58608 (13) | 0.29847 (6) | 0.0426 (3) | |
O2 | 0.63532 (6) | 0.67071 (15) | 0.40059 (7) | 0.0525 (3) | |
O3 | 0.62890 (7) | 0.69783 (14) | 0.21861 (7) | 0.0529 (3) | |
O4 | 0.47794 (8) | 0.64402 (17) | 0.07088 (7) | 0.0620 (3) | |
H4 | 0.4288 | 0.6281 | 0.0334 | 0.093* | |
O5 | 0.31225 (8) | 0.58768 (17) | 0.01722 (7) | 0.0616 (3) | |
O6 | 0.16597 (7) | 0.53866 (16) | 0.06686 (7) | 0.0587 (3) | |
O7 | 0.00047 (7) | 0.53200 (18) | 0.39654 (8) | 0.0674 (4) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0497 (8) | 0.0430 (8) | 0.0356 (7) | −0.0008 (6) | 0.0155 (6) | 0.0017 (6) |
C2 | 0.0492 (8) | 0.0354 (7) | 0.0431 (7) | −0.0009 (6) | 0.0160 (6) | 0.0014 (6) |
C3 | 0.0547 (8) | 0.0332 (7) | 0.0489 (8) | −0.0023 (6) | 0.0253 (7) | 0.0009 (6) |
C4 | 0.0654 (9) | 0.0362 (7) | 0.0389 (7) | −0.0008 (6) | 0.0243 (7) | 0.0009 (6) |
C5 | 0.0552 (8) | 0.0343 (7) | 0.0380 (7) | 0.0016 (6) | 0.0165 (6) | 0.0008 (5) |
C6 | 0.0486 (8) | 0.0334 (7) | 0.0396 (7) | 0.0022 (6) | 0.0175 (6) | 0.0026 (5) |
C7 | 0.0626 (9) | 0.0394 (7) | 0.0359 (7) | 0.0056 (7) | 0.0132 (6) | 0.0033 (6) |
C8 | 0.0513 (8) | 0.0415 (8) | 0.0394 (7) | 0.0053 (6) | 0.0074 (6) | 0.0014 (6) |
C9 | 0.0469 (8) | 0.0343 (7) | 0.0410 (7) | 0.0030 (6) | 0.0084 (6) | −0.0001 (6) |
C10 | 0.0448 (7) | 0.0396 (7) | 0.0418 (7) | 0.0011 (6) | 0.0086 (6) | 0.0013 (6) |
C11 | 0.0455 (8) | 0.0488 (8) | 0.0424 (7) | −0.0076 (6) | 0.0096 (6) | −0.0027 (6) |
C12 | 0.0533 (8) | 0.0552 (9) | 0.0432 (7) | −0.0080 (7) | 0.0143 (6) | −0.0058 (7) |
C13 | 0.0476 (8) | 0.0517 (9) | 0.0487 (8) | −0.0052 (7) | 0.0139 (6) | 0.0020 (7) |
C14 | 0.0525 (9) | 0.0538 (9) | 0.0633 (9) | −0.0156 (7) | 0.0143 (7) | −0.0097 (8) |
C15 | 0.0593 (9) | 0.0490 (9) | 0.0544 (8) | −0.0080 (7) | 0.0159 (7) | −0.0123 (7) |
C16 | 0.0522 (9) | 0.0982 (14) | 0.0450 (8) | −0.0076 (9) | 0.0092 (7) | 0.0153 (9) |
C17 | 0.0725 (12) | 0.0621 (11) | 0.1037 (14) | 0.0102 (9) | 0.0500 (11) | 0.0093 (10) |
C18 | 0.0770 (12) | 0.0918 (15) | 0.0642 (11) | −0.0132 (11) | 0.0088 (9) | −0.0287 (10) |
C19 | 0.0579 (10) | 0.0963 (15) | 0.0901 (13) | −0.0257 (10) | 0.0288 (9) | −0.0111 (12) |
O1 | 0.0438 (5) | 0.0456 (5) | 0.0367 (5) | −0.0003 (4) | 0.0121 (4) | 0.0005 (4) |
O2 | 0.0473 (6) | 0.0639 (7) | 0.0455 (5) | −0.0059 (5) | 0.0154 (4) | 0.0045 (5) |
O3 | 0.0624 (6) | 0.0430 (6) | 0.0640 (6) | −0.0042 (5) | 0.0357 (5) | 0.0008 (5) |
O4 | 0.0791 (8) | 0.0728 (8) | 0.0406 (5) | −0.0097 (6) | 0.0290 (5) | −0.0025 (5) |
O5 | 0.0754 (7) | 0.0706 (8) | 0.0348 (5) | 0.0027 (6) | 0.0141 (5) | 0.0057 (5) |
O6 | 0.0545 (6) | 0.0664 (7) | 0.0439 (6) | 0.0046 (5) | 0.0029 (5) | −0.0018 (5) |
O7 | 0.0587 (7) | 0.0816 (9) | 0.0676 (7) | −0.0227 (6) | 0.0294 (6) | −0.0130 (6) |
C1—H1 | 0.9300 | C12—C13 | 1.390 (2) |
C1—C2 | 1.3845 (19) | C13—C14 | 1.382 (2) |
C1—C6 | 1.3774 (19) | C13—O7 | 1.3580 (18) |
C2—C3 | 1.408 (2) | C14—H14 | 0.9300 |
C2—O2 | 1.3552 (17) | C14—C15 | 1.389 (2) |
C3—C4 | 1.373 (2) | C15—H15 | 0.9300 |
C3—O3 | 1.3755 (17) | C16—H16A | 0.9600 |
C4—C5 | 1.419 (2) | C16—H16B | 0.9600 |
C4—O4 | 1.3543 (17) | C16—H16C | 0.9600 |
C5—C6 | 1.3920 (19) | C16—O2 | 1.4347 (18) |
C5—C7 | 1.437 (2) | C17—H17A | 0.9600 |
C6—O1 | 1.3685 (16) | C17—H17B | 0.9600 |
C7—C8 | 1.446 (2) | C17—H17C | 0.9600 |
C7—O5 | 1.2531 (17) | C17—O3 | 1.408 (2) |
C8—C9 | 1.358 (2) | C18—H18A | 0.9600 |
C8—O6 | 1.3761 (17) | C18—H18B | 0.9600 |
C9—C10 | 1.469 (2) | C18—H18C | 0.9600 |
C9—O1 | 1.3644 (16) | C18—O6 | 1.438 (2) |
C10—C11 | 1.395 (2) | C19—H19A | 0.9600 |
C10—C15 | 1.388 (2) | C19—H19B | 0.9600 |
C11—H11 | 0.9300 | C19—H19C | 0.9600 |
C11—C12 | 1.373 (2) | C19—O7 | 1.424 (2) |
C12—H12 | 0.9300 | O4—H4 | 0.8200 |
C2—C1—H1 | 121.0 | O7—C13—C14 | 125.10 (14) |
C6—C1—H1 | 121.0 | C13—C14—H14 | 120.0 |
C6—C1—C2 | 117.96 (12) | C13—C14—C15 | 119.95 (14) |
C1—C2—C3 | 121.20 (13) | C15—C14—H14 | 120.0 |
O2—C2—C1 | 123.76 (12) | C10—C15—C14 | 121.25 (14) |
O2—C2—C3 | 115.04 (12) | C10—C15—H15 | 119.4 |
C4—C3—C2 | 119.61 (13) | C14—C15—H15 | 119.4 |
C4—C3—O3 | 120.00 (12) | H16A—C16—H16B | 109.5 |
O3—C3—C2 | 120.30 (13) | H16A—C16—H16C | 109.5 |
C3—C4—C5 | 120.51 (12) | H16B—C16—H16C | 109.5 |
O4—C4—C3 | 119.16 (13) | O2—C16—H16A | 109.5 |
O4—C4—C5 | 120.33 (13) | O2—C16—H16B | 109.5 |
C4—C5—C7 | 122.26 (12) | O2—C16—H16C | 109.5 |
C6—C5—C4 | 117.47 (13) | H17A—C17—H17B | 109.5 |
C6—C5—C7 | 120.26 (13) | H17A—C17—H17C | 109.5 |
C1—C6—C5 | 123.22 (13) | H17B—C17—H17C | 109.5 |
O1—C6—C1 | 115.93 (11) | O3—C17—H17A | 109.5 |
O1—C6—C5 | 120.85 (12) | O3—C17—H17B | 109.5 |
C5—C7—C8 | 115.41 (12) | O3—C17—H17C | 109.5 |
O5—C7—C5 | 122.41 (14) | H18A—C18—H18B | 109.5 |
O5—C7—C8 | 122.18 (13) | H18A—C18—H18C | 109.5 |
C9—C8—C7 | 121.73 (13) | H18B—C18—H18C | 109.5 |
C9—C8—O6 | 118.29 (14) | O6—C18—H18A | 109.5 |
O6—C8—C7 | 119.66 (12) | O6—C18—H18B | 109.5 |
C8—C9—C10 | 128.17 (13) | O6—C18—H18C | 109.5 |
C8—C9—O1 | 120.90 (13) | H19A—C19—H19B | 109.5 |
O1—C9—C10 | 110.79 (11) | H19A—C19—H19C | 109.5 |
C11—C10—C9 | 119.26 (12) | H19B—C19—H19C | 109.5 |
C15—C10—C9 | 122.96 (13) | O7—C19—H19A | 109.5 |
C15—C10—C11 | 117.78 (14) | O7—C19—H19B | 109.5 |
C10—C11—H11 | 119.3 | O7—C19—H19C | 109.5 |
C12—C11—C10 | 121.36 (13) | C9—O1—C6 | 120.71 (10) |
C12—C11—H11 | 119.3 | C2—O2—C16 | 116.96 (11) |
C11—C12—H12 | 119.9 | C3—O3—C17 | 115.09 (12) |
C11—C12—C13 | 120.29 (14) | C4—O4—H4 | 109.5 |
C13—C12—H12 | 119.9 | C8—O6—C18 | 115.31 (13) |
C14—C13—C12 | 119.34 (14) | C13—O7—C19 | 118.32 (13) |
O7—C13—C12 | 115.55 (13) | ||
C1—C2—C3—C4 | −1.7 (2) | C8—C9—C10—C11 | −142.84 (15) |
C1—C2—C3—O3 | 174.72 (12) | C8—C9—C10—C15 | 37.3 (2) |
C1—C2—O2—C16 | 6.5 (2) | C8—C9—O1—C6 | −2.98 (19) |
C1—C6—O1—C9 | −176.54 (12) | C9—C8—O6—C18 | −119.21 (16) |
C2—C1—C6—C5 | 0.3 (2) | C9—C10—C11—C12 | 178.80 (13) |
C2—C1—C6—O1 | −178.99 (12) | C9—C10—C15—C14 | −179.31 (14) |
C2—C3—C4—C5 | 0.3 (2) | C10—C9—O1—C6 | −179.13 (11) |
C2—C3—C4—O4 | −179.58 (13) | C10—C11—C12—C13 | 0.5 (2) |
C2—C3—O3—C17 | 88.51 (17) | C11—C10—C15—C14 | 0.8 (2) |
C3—C2—O2—C16 | −174.02 (14) | C11—C12—C13—C14 | 0.9 (2) |
C3—C4—C5—C6 | 1.3 (2) | C11—C12—C13—O7 | −178.28 (14) |
C3—C4—C5—C7 | −179.12 (13) | C12—C13—C14—C15 | −1.4 (2) |
C4—C3—O3—C17 | −95.05 (17) | C12—C13—O7—C19 | −178.35 (16) |
C4—C5—C6—C1 | −1.7 (2) | C13—C14—C15—C10 | 0.5 (3) |
C4—C5—C6—O1 | 177.63 (11) | C14—C13—O7—C19 | 2.6 (2) |
C4—C5—C7—C8 | 179.28 (13) | C15—C10—C11—C12 | −1.3 (2) |
C4—C5—C7—O5 | −1.3 (2) | O1—C9—C10—C11 | 32.96 (17) |
C5—C6—O1—C9 | 4.11 (18) | O1—C9—C10—C15 | −146.90 (14) |
C5—C7—C8—C9 | 2.3 (2) | O2—C2—C3—C4 | 178.76 (12) |
C5—C7—C8—O6 | 175.71 (12) | O2—C2—C3—O3 | −4.78 (19) |
C6—C1—C2—C3 | 1.4 (2) | O3—C3—C4—C5 | −176.13 (12) |
C6—C1—C2—O2 | −179.15 (13) | O3—C3—C4—O4 | 4.0 (2) |
C6—C5—C7—C8 | −1.2 (2) | O4—C4—C5—C6 | −178.79 (13) |
C6—C5—C7—O5 | 178.25 (13) | O4—C4—C5—C7 | 0.8 (2) |
C7—C5—C6—C1 | 178.74 (12) | O5—C7—C8—C9 | −177.12 (14) |
C7—C5—C6—O1 | −2.0 (2) | O5—C7—C8—O6 | −3.7 (2) |
C7—C8—C9—C10 | 175.13 (13) | O6—C8—C9—C10 | 1.6 (2) |
C7—C8—C9—O1 | −0.3 (2) | O6—C8—C9—O1 | −173.81 (12) |
C7—C8—O6—C18 | 67.14 (19) | O7—C13—C14—C15 | 177.69 (15) |
Experimental details
Crystal data | |
Chemical formula | C19H18O7 |
Mr | 358.33 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 295 |
a, b, c (Å) | 16.6029 (3), 7.40255 (12), 14.8666 (3) |
β (°) | 110.487 (2) |
V (Å3) | 1711.60 (6) |
Z | 4 |
Radiation type | Cu Kα |
µ (mm−1) | 0.90 |
Crystal size (mm) | 0.26 × 0.21 × 0.18 |
Data collection | |
Diffractometer | Oxford Diffraction Xcalibur Sapphire3 Gemini Ultra CCD |
Absorption correction | Multi-scan (CrysAlis PRO; Agilent, 2011) |
Tmin, Tmax | 0.596, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5568, 2681, 2380 |
Rint | 0.016 |
(sin θ/λ)max (Å−1) | 0.576 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.035, 0.097, 1.03 |
No. of reflections | 2681 |
No. of parameters | 241 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.14, −0.13 |
Computer programs: CrysAlis PRO (Agilent, 2011), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), OLEX2 (Dolomanov et al., 2009).
Acknowledgements
This work was supported financially by the National Natural Science Foundation of China (No. 81072535) and the Team Project of the Natural Science Foundation of Guangdong Province (No. 8351063201000003).
References
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The title compound, the flavonoid C19H18O7 [systematic name 5-hydroxy-3,6,7-trimethoxy-2-(4-methoxyphenyl)-4H-1-benzopyran-4-one], (Fig. 1) was originally sythesised from trimethoxyacetophenone (Goldsworthy & Robert, 1936). It was also isolated from Artemisia annua (Sy & Brown, 1998), Laggera pterodonta (Yang et al., 2007) and Aites agnus-castus (Masateru et al., 2009). The flavonoid was also proved to possess significant anti-hepatotoxic activity (Chhaya et al., 2007). The present compound was isolated from the traditional Chinese medicine Laggera alata. In the crystal structure, the dihedral angle between the plane of the benzene ring A and the pyran plane C is 1.72 (3)°, while that between the benzene ring A and the phenyl ring B is 37.39 (5)°. The molecular conformation is stabilized by an intramolecular phenol O—H···Oketone hydrogen-bonding interaction (Table 1).