Acta Cryst. (2008). E64, o822 [ doi:10.1107/S1600536808009355 ]
The title compound, C17H16O6, was isolated from the Chinese Tibetan medicinal plant Artemisia sphaerocephala Kraschen. The molecular conformation is consolidated by two intramolecular O-H
O hydrogen bonds. A further intermolecular O-HO hydrogen bond leads to chains along [010] in the crystal structure.
The air-dried whole plant (5.1 kg) was ground into powder and extracted three times with 95% EtOH for 3 h each time. The concentrated extract was dispersed in water and partitioned successively with petroleum ether, CHCl3, EtOAC and n-BuOH. The chloroform fraction (115 g) was subjected to silics gel with petroleum ether-acetone (9:1) to yield two fractions (Frs. 1–2). Fraction 2 (50 g) was subjected to silics gel with petroleum ether-EtOAC (50:1, 45:1, 40:1, 30:1) to yield six fractions. After a week, the crude title compound (20 mg) was crystallized from the fourth fraction. After recrystallization from petroleum ether-EtOAC, colourless blocks of (I) arose, with a melting point of 475 K. The molecular formula, C17H16O6, was established by ESIMS m/z:316(M+). Spectroscopic analysis, 1H NMR (400 MHz, DMSO-d6) δ: 12.15 (1H, s), 6.08 (1H, d, J=2.2 Hz), 6.05 (1H, d, J=2.2 Hz), 5.47 (1H, dd, J=12.6 Hz, 3.0 Hz), 3.20 (1H, dd, J=15.5 Hz, 12.6 Hz), 2.82 (1H, dd, J=15.5 Hz, 3.0 Hz); 13 C NMR (400 MHz, DMSO-d6) δ: 197.0 (C-4), 168.0 (C-7), 163.8 (C-5), 163.1 (C-9), 147.8 (C-4'), 146.7 (C-3'), 131.8 (C-1'), 117.9 (C-6'), 113.5 (C-5'), 111.3 (C-2'), 102.9 (C-10), 94.6 (C-6), 93.7 (C-8), 79.0 (C-2), 42.6 (C-3), 55.4 (4'-OCH3), 55.3 (7-OCH3).
Anomalous dispersion was negligible and Friedel pairs were merged before refinement.
The H atoms were geometrically placed (C-H = 0.93–0.98Å, O—H = 0.82 Å), and refined as riding with Uiso(H)=1.2Ueq(C) or Uiso(H)=1.5Ueq(O or methyl C).
Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: PLATON (Spek, 2003).
![[Figure 1]](./hb2716fig1thm.gif)
| Fig. 1. The molecular structure of (I), with displacement ellipsoids for the non-hydrogen atoms drawn at the 40% probability level. Hydrogen bonds are shown as double dashed lines. |
![[Figure 2]](./hb2716fig2thm.gif)
| Fig. 2. Fragment of the one-dimensional chain structure of (I) with hydrogen bonds shown as dashed lines. |
| C17H16O6 | F000 = 332 |
| Mr = 316.30 | Dx = 1.395 Mg m−3 |
| Monoclinic, P21 | Mo Kα radiation λ = 0.71073 Å |
| Hall symbol: P 2y b | Cell parameters from 4047 reflections |
| a = 5.4234 (12) Å | θ = 2.6–27.5º |
| b = 9.293 (2) Å | µ = 0.11 mm−1 |
| c = 14.940 (3) Å | T = 296 (2) K |
| β = 91.039 (2)º | Block, colorless |
| V = 752.9 (3) Å3 | 0.22 × 0.18 × 0.12 mm |
| Z = 2 |
| Bruker SMART APEX CCD diffractometer | 1581 independent reflections |
| Radiation source: fine-focus sealed tube | 1489 reflections with I > 2σ(I) |
| Monochromator: graphite | Rint = 0.019 |
| T = 296(2) K | θmax = 26.0º |
| φ and ω scans | θmin = 2.6º |
| Absorption correction: multi-scan (SADABS; Bruker, 2001) | h = −6→6 |
| Tmin = 0.977, Tmax = 0.987 | k = −11→11 |
| 7958 measured reflections | l = −18→18 |
| 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)] = 0.028 | H-atom parameters constrained |
| wR(F2) = 0.077 | w = 1/[σ2(Fo2) + (0.0485P)2 + 0.0531P] where P = (Fo2 + 2Fc2)/3 |
| S = 1.06 | (Δ/σ)max < 0.001 |
| 1581 reflections | Δρmax = 0.11 e Å−3 |
| 212 parameters | Δρmin = −0.14 e Å−3 |
| 1 restraint | Extinction correction: none |
| Primary atom site location: structure-invariant direct methods |
| C17H16O6 | V = 752.9 (3) Å3 |
| Mr = 316.30 | Z = 2 |
| Monoclinic, P21 | Mo Kα |
| a = 5.4234 (12) Å | µ = 0.11 mm−1 |
| b = 9.293 (2) Å | T = 296 (2) K |
| c = 14.940 (3) Å | 0.22 × 0.18 × 0.12 mm |
| β = 91.039 (2)º |
| Bruker SMART APEX CCD diffractometer | 1581 independent reflections |
| Absorption correction: multi-scan (SADABS; Bruker, 2001) | 1489 reflections with I > 2σ(I) |
| Tmin = 0.977, Tmax = 0.987 | Rint = 0.019 |
| 7958 measured reflections |
| R[F2 > 2σ(F2)] = 0.028 | 1 restraint |
| wR(F2) = 0.077 | H-atom parameters constrained |
| S = 1.06 | Δρmax = 0.11 e Å−3 |
| 1581 reflections | Δρmin = −0.14 e Å−3 |
| 212 parameters |
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. |
| x | y | z | Uiso*/Ueq | ||
| O1 | 0.3993 (2) | 0.73089 (16) | 0.11833 (7) | 0.0443 (3) | |
| O2 | 0.8292 (3) | 0.9824 (2) | 0.28305 (11) | 0.0697 (5) | |
| O3 | 0.6055 (3) | 0.8761 (2) | 0.41875 (10) | 0.0703 (5) | |
| H3 | 0.7086 | 0.9231 | 0.3919 | 0.105* | |
| O4 | −0.0461 (3) | 0.54437 (19) | 0.35407 (9) | 0.0532 (4) | |
| O5 | 0.5698 (3) | 0.79981 (18) | −0.28802 (9) | 0.0582 (4) | |
| O6 | 0.2587 (3) | 0.94212 (19) | −0.18692 (9) | 0.0595 (4) | |
| H5 | 0.2732 | 0.9377 | −0.2414 | 0.089* | |
| C1' | 0.6333 (3) | 0.7757 (2) | −0.01135 (12) | 0.0396 (4) | |
| C2 | 0.6447 (3) | 0.7700 (2) | 0.08935 (12) | 0.0407 (4) | |
| H2 | 0.7605 | 0.6942 | 0.1079 | 0.049* | |
| C2' | 0.8030 (4) | 0.7024 (2) | −0.06221 (12) | 0.0469 (5) | |
| H2' | 0.9271 | 0.6494 | −0.0338 | 0.056* | |
| C3 | 0.7244 (4) | 0.9111 (3) | 0.13314 (13) | 0.0509 (5) | |
| H3A | 0.8946 | 0.9310 | 0.1185 | 0.061* | |
| H3B | 0.6235 | 0.9889 | 0.1094 | 0.061* | |
| C3' | 0.7904 (4) | 0.7070 (2) | −0.15510 (13) | 0.0508 (5) | |
| H3' | 0.9056 | 0.6574 | −0.1886 | 0.061* | |
| C4 | 0.7001 (4) | 0.9053 (2) | 0.23342 (13) | 0.0485 (5) | |
| C4' | 0.6070 (4) | 0.7852 (2) | −0.19750 (12) | 0.0434 (4) | |
| C5 | 0.4695 (4) | 0.7986 (2) | 0.35954 (12) | 0.0472 (5) | |
| C5' | 0.4376 (3) | 0.8613 (2) | −0.14645 (12) | 0.0415 (4) | |
| C6 | 0.2845 (4) | 0.7110 (3) | 0.39144 (12) | 0.0490 (5) | |
| H6 | 0.2560 | 0.7047 | 0.4525 | 0.059* | |
| C6' | 0.4503 (3) | 0.8559 (2) | −0.05446 (12) | 0.0439 (4) | |
| H6' | 0.3359 | 0.9062 | −0.0210 | 0.053* | |
| C7 | 0.1420 (3) | 0.6325 (2) | 0.33055 (12) | 0.0416 (4) | |
| C7' | 0.7267 (6) | 0.7210 (3) | −0.34504 (14) | 0.0701 (7) | |
| H7'A | 0.8943 | 0.7509 | −0.3350 | 0.105* | |
| H7'B | 0.6798 | 0.7386 | −0.4063 | 0.105* | |
| H7'C | 0.7120 | 0.6201 | −0.3324 | 0.105* | |
| C8 | 0.1841 (3) | 0.6390 (2) | 0.23879 (12) | 0.0410 (4) | |
| H8 | 0.0882 | 0.5852 | 0.1989 | 0.049* | |
| C9 | 0.3691 (3) | 0.7260 (2) | 0.20815 (11) | 0.0373 (4) | |
| C10 | 0.5161 (3) | 0.8091 (2) | 0.26731 (12) | 0.0413 (4) | |
| C11 | −0.1037 (5) | 0.5297 (3) | 0.44657 (14) | 0.0660 (7) | |
| H11A | 0.0353 | 0.4893 | 0.4784 | 0.099* | |
| H11B | −0.2436 | 0.4673 | 0.4525 | 0.099* | |
| H11C | −0.1413 | 0.6225 | 0.4710 | 0.099* |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| O1 | 0.0462 (7) | 0.0580 (8) | 0.0285 (6) | −0.0111 (6) | 0.0003 (5) | 0.0007 (6) |
| O2 | 0.0826 (11) | 0.0731 (11) | 0.0531 (9) | −0.0365 (10) | −0.0075 (8) | −0.0084 (8) |
| O3 | 0.0893 (12) | 0.0821 (12) | 0.0389 (7) | −0.0298 (10) | −0.0109 (7) | −0.0116 (8) |
| O4 | 0.0558 (8) | 0.0709 (10) | 0.0330 (7) | −0.0121 (7) | 0.0052 (6) | 0.0056 (7) |
| O5 | 0.0790 (10) | 0.0625 (9) | 0.0332 (7) | 0.0170 (8) | 0.0059 (6) | −0.0006 (7) |
| O6 | 0.0639 (9) | 0.0755 (11) | 0.0391 (8) | 0.0270 (8) | −0.0006 (7) | 0.0045 (8) |
| C1' | 0.0429 (9) | 0.0412 (10) | 0.0346 (9) | −0.0019 (8) | 0.0026 (7) | 0.0034 (8) |
| C2 | 0.0407 (9) | 0.0457 (10) | 0.0357 (9) | −0.0013 (8) | −0.0004 (7) | 0.0048 (8) |
| C2' | 0.0465 (10) | 0.0504 (11) | 0.0438 (10) | 0.0109 (9) | 0.0036 (8) | 0.0073 (9) |
| C3 | 0.0557 (11) | 0.0530 (12) | 0.0440 (11) | −0.0138 (10) | 0.0009 (9) | 0.0023 (9) |
| C3' | 0.0552 (11) | 0.0531 (12) | 0.0446 (11) | 0.0140 (10) | 0.0117 (9) | 0.0014 (10) |
| C4 | 0.0525 (11) | 0.0484 (11) | 0.0443 (10) | −0.0106 (10) | −0.0054 (9) | −0.0026 (9) |
| C4' | 0.0561 (10) | 0.0409 (10) | 0.0334 (9) | 0.0030 (9) | 0.0069 (8) | 0.0024 (8) |
| C5 | 0.0568 (11) | 0.0521 (12) | 0.0326 (9) | −0.0008 (10) | −0.0075 (8) | −0.0051 (8) |
| C5' | 0.0443 (9) | 0.0430 (10) | 0.0372 (9) | 0.0055 (8) | 0.0010 (8) | 0.0040 (8) |
| C6 | 0.0597 (11) | 0.0605 (12) | 0.0267 (8) | −0.0003 (10) | 0.0001 (8) | −0.0005 (9) |
| C6' | 0.0465 (10) | 0.0484 (10) | 0.0370 (9) | 0.0089 (9) | 0.0075 (8) | 0.0013 (8) |
| C7 | 0.0422 (10) | 0.0491 (11) | 0.0335 (9) | 0.0010 (8) | 0.0014 (7) | 0.0047 (8) |
| C7' | 0.1016 (19) | 0.0707 (16) | 0.0385 (11) | 0.0154 (15) | 0.0164 (11) | −0.0066 (12) |
| C8 | 0.0409 (9) | 0.0494 (10) | 0.0326 (9) | −0.0038 (8) | −0.0039 (7) | −0.0016 (8) |
| C9 | 0.0405 (9) | 0.0424 (10) | 0.0290 (8) | 0.0004 (8) | −0.0028 (7) | 0.0007 (8) |
| C10 | 0.0450 (9) | 0.0443 (10) | 0.0346 (9) | −0.0016 (8) | −0.0031 (7) | −0.0011 (8) |
| C11 | 0.0706 (15) | 0.0886 (18) | 0.0393 (11) | −0.0062 (14) | 0.0133 (10) | 0.0150 (12) |
| O1—C9 | 1.3555 (19) | C3'—C4' | 1.377 (3) |
| O1—C2 | 1.453 (2) | C3'—H3' | 0.9300 |
| O2—C4 | 1.239 (2) | C4—C10 | 1.439 (3) |
| O3—C5 | 1.350 (2) | C4'—C5' | 1.397 (3) |
| O3—H3 | 0.8200 | C5—C6 | 1.383 (3) |
| O4—C7 | 1.359 (2) | C5—C10 | 1.409 (3) |
| O4—C11 | 1.429 (2) | C5'—C6' | 1.376 (2) |
| O5—C4' | 1.370 (2) | C6—C7 | 1.390 (3) |
| O5—C7' | 1.419 (3) | C6—H6 | 0.9300 |
| O6—C5' | 1.360 (2) | C6'—H6' | 0.9300 |
| O6—H5 | 0.8200 | C7—C8 | 1.395 (2) |
| C1'—C2' | 1.383 (3) | C7'—H7'A | 0.9600 |
| C1'—C6' | 1.390 (3) | C7'—H7'B | 0.9600 |
| C1'—C2 | 1.506 (2) | C7'—H7'C | 0.9600 |
| C2—C3 | 1.525 (3) | C8—C9 | 1.373 (3) |
| C2—H2 | 0.9800 | C8—H8 | 0.9300 |
| C2'—C3' | 1.389 (3) | C9—C10 | 1.409 (2) |
| C2'—H2' | 0.9300 | C11—H11A | 0.9600 |
| C3—C4 | 1.507 (3) | C11—H11B | 0.9600 |
| C3—H3A | 0.9700 | C11—H11C | 0.9600 |
| C3—H3B | 0.9700 | ||
| C9—O1—C2 | 115.53 (13) | C6—C5—C10 | 121.46 (17) |
| C5—O3—H3 | 109.5 | O6—C5'—C6' | 119.12 (16) |
| C7—O4—C11 | 119.06 (17) | O6—C5'—C4' | 120.52 (16) |
| C4'—O5—C7' | 117.54 (18) | C6'—C5'—C4' | 120.37 (17) |
| C5'—O6—H5 | 109.5 | C5—C6—C7 | 118.79 (17) |
| C2'—C1'—C6' | 119.09 (16) | C5—C6—H6 | 120.6 |
| C2'—C1'—C2 | 121.06 (16) | C7—C6—H6 | 120.6 |
| C6'—C1'—C2 | 119.86 (16) | C5'—C6'—C1' | 120.31 (17) |
| O1—C2—C1' | 106.57 (13) | C5'—C6'—H6' | 119.8 |
| O1—C2—C3 | 109.97 (16) | C1'—C6'—H6' | 119.8 |
| C1'—C2—C3 | 113.88 (16) | O4—C7—C6 | 123.92 (16) |
| O1—C2—H2 | 108.8 | O4—C7—C8 | 114.67 (16) |
| C1'—C2—H2 | 108.8 | C6—C7—C8 | 121.40 (17) |
| C3—C2—H2 | 108.8 | O5—C7'—H7'A | 109.5 |
| C1'—C2'—C3' | 120.83 (17) | O5—C7'—H7'B | 109.5 |
| C1'—C2'—H2' | 119.6 | H7'A—C7'—H7'B | 109.5 |
| C3'—C2'—H2' | 119.6 | O5—C7'—H7'C | 109.5 |
| C4—C3—C2 | 111.48 (16) | H7'A—C7'—H7'C | 109.5 |
| C4—C3—H3A | 109.3 | H7'B—C7'—H7'C | 109.5 |
| C2—C3—H3A | 109.3 | C9—C8—C7 | 119.13 (17) |
| C4—C3—H3B | 109.3 | C9—C8—H8 | 120.4 |
| C2—C3—H3B | 109.3 | C7—C8—H8 | 120.4 |
| H3A—C3—H3B | 108.0 | O1—C9—C8 | 116.84 (16) |
| C4'—C3'—C2' | 119.86 (17) | O1—C9—C10 | 121.70 (16) |
| C4'—C3'—H3' | 120.1 | C8—C9—C10 | 121.44 (15) |
| C2'—C3'—H3' | 120.1 | C5—C10—C9 | 117.77 (17) |
| O2—C4—C10 | 122.49 (18) | C5—C10—C4 | 121.68 (17) |
| O2—C4—C3 | 121.02 (19) | C9—C10—C4 | 120.51 (16) |
| C10—C4—C3 | 116.47 (17) | O4—C11—H11A | 109.5 |
| O5—C4'—C3' | 126.74 (17) | O4—C11—H11B | 109.5 |
| O5—C4'—C5' | 113.72 (17) | H11A—C11—H11B | 109.5 |
| C3'—C4'—C5' | 119.53 (16) | O4—C11—H11C | 109.5 |
| O3—C5—C6 | 118.64 (17) | H11A—C11—H11C | 109.5 |
| O3—C5—C10 | 119.90 (18) | H11B—C11—H11C | 109.5 |
| C9—O1—C2—C1' | −177.36 (16) | C2'—C1'—C6'—C5' | 0.5 (3) |
| C9—O1—C2—C3 | −53.5 (2) | C2—C1'—C6'—C5' | −179.73 (18) |
| C2'—C1'—C2—O1 | −128.91 (19) | C11—O4—C7—C6 | −0.2 (3) |
| C6'—C1'—C2—O1 | 51.3 (2) | C11—O4—C7—C8 | 179.76 (19) |
| C2'—C1'—C2—C3 | 109.7 (2) | C5—C6—C7—O4 | −179.2 (2) |
| C6'—C1'—C2—C3 | −70.1 (2) | C5—C6—C7—C8 | 0.8 (3) |
| C6'—C1'—C2'—C3' | −0.8 (3) | O4—C7—C8—C9 | 179.50 (18) |
| C2—C1'—C2'—C3' | 179.46 (18) | C6—C7—C8—C9 | −0.6 (3) |
| O1—C2—C3—C4 | 52.9 (2) | C2—O1—C9—C8 | −155.13 (17) |
| C1'—C2—C3—C4 | 172.44 (16) | C2—O1—C9—C10 | 26.5 (3) |
| C1'—C2'—C3'—C4' | 0.0 (3) | C7—C8—C9—O1 | −178.69 (17) |
| C2—C3—C4—O2 | 154.3 (2) | C7—C8—C9—C10 | −0.3 (3) |
| C2—C3—C4—C10 | −27.3 (3) | O3—C5—C10—C9 | 180.00 (19) |
| C7'—O5—C4'—C3' | 3.6 (3) | C6—C5—C10—C9 | −0.6 (3) |
| C7'—O5—C4'—C5' | −177.3 (2) | O3—C5—C10—C4 | −2.5 (3) |
| C2'—C3'—C4'—O5 | −179.8 (2) | C6—C5—C10—C4 | 176.9 (2) |
| C2'—C3'—C4'—C5' | 1.1 (3) | O1—C9—C10—C5 | 179.19 (17) |
| O5—C4'—C5'—O6 | −0.8 (3) | C8—C9—C10—C5 | 0.9 (3) |
| C3'—C4'—C5'—O6 | 178.4 (2) | O1—C9—C10—C4 | 1.6 (3) |
| O5—C4'—C5'—C6' | 179.39 (18) | C8—C9—C10—C4 | −176.67 (19) |
| C3'—C4'—C5'—C6' | −1.4 (3) | O2—C4—C10—C5 | 0.9 (3) |
| O3—C5—C6—C7 | 179.2 (2) | C3—C4—C10—C5 | −177.44 (19) |
| C10—C5—C6—C7 | −0.2 (3) | O2—C4—C10—C9 | 178.4 (2) |
| O6—C5'—C6'—C1' | −179.19 (19) | C3—C4—C10—C9 | 0.0 (3) |
| C4'—C5'—C6'—C1' | 0.6 (3) |
| D—H···A | D—H | H···A | D···A | D—H···A |
| O3—H3···O2 | 0.82 | 1.85 | 2.579 (2) | 148 |
| O6—H5···O5 | 0.82 | 2.18 | 2.640 (2) | 116 |
| O6—H5···O4i | 0.82 | 2.29 | 2.892 (2) | 130 |
| Symmetry codes: (i) −x, y+1/2, −z. |
| D—H···A | D—H | H···A | D···A | D—H···A |
| O3—H3···O2 | 0.82 | 1.85 | 2.579 (2) | 148 |
| O6—H5···O5 | 0.82 | 2.18 | 2.640 (2) | 116 |
| O6—H5···O4i | 0.82 | 2.29 | 2.892 (2) | 130 |
| Symmetry codes: (i) −x, y+1/2, −z. |
Bruker (2001). SAINT-Plus, SMART and SADABS. Bruker AXS, Inc., Madison, Wisconsin, USA.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.
Spek, A. L. (2003). J. Appl. Cryst. 36, 7–13.
Zhao, D. B., Li, L. X., Liu, X. H., Li, M. J. & Wang, W. L. (2007). Chin. Chem. Lett. 18, 551–557.
As part of the ongoing investigations of the Chinese Tibetan medicinal plant Artemisia sphaerocephala Kraschen (Zhao et al., 2007), we now report the isolation and structure of the flavone-related title compound, (I).
Compound (I) consists of three-ring system, including a phenyl ring and a benzopyrone fused ring (Fig.1). The C–O bond distances range from 1.239 (2) to 1.453 (2) Å, in which C4–O2 [1.239 (2) Å] is typical for a C=O double-bond. The S(6) ring of O1/C2/C3/C4/C9/C10 in (I) is nonplanar, charactrtized by a O1–C2–C3–C4 torsion angle of 52.9 (2) °. Atom C2 is chiral, but the absolute structure of (I) could not be established from the present experiment. The dihedral angle between the aromatic ring planes is 77.26 (9) °.
Two intramolecular O-H···O hydrogen bonds (Table 1) help to establish the molecular conformation, both constructing S(6) rings. In addition, an intermolecular O-H···O link leads to [010] chains in the crystal (Fig. 2).