PMCCPMCCPMCC

Search tips
Search criteria 

Advanced

 
Logo of actaeInternational Union of Crystallographysearchopen accessarticle submissionjournal home pagethis article
 
Acta Crystallogr Sect E Struct Rep Online. 2008 July 1; 64(Pt 7): o1305.
Published online 2008 June 19. doi:  10.1107/S1600536808018266
PMCID: PMC2961722

Semisynthetic roxburghin tetra­methyl ether

Abstract

The title mol­ecule, (E)-2,3′,4,5-tetra­methoxy­stilbene, C18H20O4, is virtually planar. The angle between the two benzene rings is 4.06 (6)°. The inter­molecular inter­actions present in the structure are weak. There are C—H(...)O hydrogen bonds and C—H(...)π-electron ring inter­actions. The mol­ecules are ordered into planes that are parallel to (An external file that holds a picture, illustration, etc.
Object name is e-64-o1305-efi1.jpg01). The distance between adjacent planes is about 3.3 Å and therefore π–π electron inter­actions between the aromatic planes are also plausible.

Related literature

For the importance and useful applications of stilbenoid compounds, see: Cushman et al. (1991 [triangle]); Nakamura et al. (2006 [triangle]). For the precursors of the title compound, see: Krishnamurty & Maheshwari (1988 [triangle]); Anjaneyulu et al. (1990 [triangle]); Wang et al. (1988 [triangle]); Murillo (2001 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-64-o1305-scheme1.jpg

Experimental

Crystal data

  • C18H20O4
  • M r = 300.34
  • Triclinic, An external file that holds a picture, illustration, etc.
Object name is e-64-o1305-efi2.jpg
  • a = 7.9633 (4) Å
  • b = 9.2454 (5) Å
  • c = 11.6194 (5) Å
  • α = 73.400 (2)°
  • β = 75.479 (3)°
  • γ = 70.335 (2)°
  • V = 760.59 (7) Å3
  • Z = 2
  • Mo Kα radiation
  • μ = 0.09 mm−1
  • T = 150 (2) K
  • 0.35 × 0.10 × 0.04 mm

Data collection

  • Nonius KappaCCD diffractometer
  • Absorption correction: none
  • 8260 measured reflections
  • 4391 independent reflections
  • 2785 reflections with I > 2σ(I)
  • R int = 0.025

Refinement

  • R[F 2 > 2σ(F 2)] = 0.047
  • wR(F 2) = 0.136
  • S = 0.98
  • 4391 reflections
  • 203 parameters
  • H-atom parameters constrained
  • Δρmax = 0.29 e Å−3
  • Δρmin = −0.23 e Å−3

Data collection: COLLECT (Nonius, 1998 [triangle]); cell refinement: SCALEPACK (Otwinowski & Minor, 1997 [triangle]); data reduction: SCALEPACK; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: SHELXTL/PC (Sheldrick, 2008 [triangle]); software used to prepare material for publication: SHELXL97.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808018266/fb2091sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808018266/fb2091Isup2.hkl

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

Acknowledgments

The authors thank Colciencias and Universidad de Antioquia (Programa de Sostenibilidad) for financial support.

supplementary crystallographic information

Comment

Stilbenoid compounds display significant biological activities (Cushman et al., 1991; Nakamura et al., 2006). Resveratrol and its derivatives deserve considerable attention for their physiological properties and their role in defense mechanisms of the higher plants. The Roxburghin tetramethyl ether (E)-2,3',4,5,-tetramethoxystilbene) that is an analogue of resveratrol, has been originally obtained by modifications of roxburghin (Krishnamurty & Maheshwari, 1988). It has been completely synthesized by the Perkins modified reaction (Anjaneyulu et al., 1990). In addition to the crystal structure determination, we report an efficient synthesis of this product by the cross-metathesis of 3-methoxystyrene and 2,4,5-trimethoxystyrene, the latter having been obtained as a natural product from the bark of Duguetia colombiana (Annonaceae) (Wang et al., 1988; Murillo, 2001).

Experimental

The catalyst (Grubbs second generation, 9 mg, 0.01 mmol), 2,4,5-trimethoxystyrene (39 mg, 0.2 mmol) and 2-methoxystyrene (277 mg, 2.0 mmol) were disolved in dry toluene (10 ml). The solution was refluxed under nitrogen for 24 h at 393 K. The compound was purified by a flash column chromatography with silica gel using hexane/ethylacetate 9:1 as an eluent. The title compound (30.0 mg) was obtained as a yellow powder in a yield of 50.0%.

Suitable crystals (pale yellow needles, 0.35 x 0.10 x 0.04 mm average size) were obtained by slow evaporation in a two solvent system (hexane/ethylacetate 1:1). The identity and purity of the obtained compound was confirmed by spectroscopic methods.

(E)-1,2,4-trimethoxy-5-(3-methoxystyryl)benzene(Roxburghin tetramethyl ether): pale yellow needles, 1H-NMR: (CDCl3,300.13 MHz, numeration acording to ellipsoid plot) d 7.42 (d, J= 16.4 Hz, H-7), 7.26 (dd, J = 8.3,7.7 Hz, H-15), 7.12 (s, H-6), 7.12 (d, J= 7.7 Hz, H-16), 7.06 (s, H-12), 6.79 (d, J= 8.3 Hz, H-14), 6.54 (s, H-3), 3.92 (s, C-2-OCH3),3.92 (s, C-1-OCH3), 3.87 (s, C-4-OCH3),3.85 (s, C-13-OCH3); 13C (CDCl3, 75.47 MHz) d 160.2 (C-13), 152.2 (C-4), 150.1 (C-2),143.8 (C-1), 140.0 (C-11), 129.9 (C-15), 127.1 (C-8), 123.7 (C-7), 119.5 (C-16),118.6 (C-5), 113.1 (C-12), 111.9 (C-6), 109.8 (C-14), 98.1 (C-3), 57.1 (C-17), 56.9(C-18), 56.5 (C-19), 55.7 (C-20). EIMS m/z300 (100), 257 (8), 195 (12).

Refinement

All the H atoms were discernible in the difference electron-density maps. However, they were situated into idealized positions and constrained by riding model approximation. C—Hmethyl=0.98 Å; C—Haryl=0.95 Å; UisoHmethyl=1.5Ueq(Cmethyl); UisoHaryl=1.2Ueq(Caryl).

Figures

Fig. 1.
The title molecule with the displacement ellipsoids shown at the 50% probability level.

Crystal data

C18H20O4Z = 2
Mr = 300.34F000 = 320
Triclinic, P1Dx = 1.311 Mg m3
Hall symbol: -P 1Mo Kα radiation λ = 0.71073 Å
a = 7.9633 (4) ÅCell parameters from 46078 reflections
b = 9.2454 (5) Åθ = 1.0–30.0º
c = 11.6194 (5) ŵ = 0.09 mm1
α = 73.400 (2)ºT = 150 (2) K
β = 75.479 (3)ºNeedle, yellow
γ = 70.335 (2)º0.35 × 0.10 × 0.04 mm
V = 760.59 (7) Å3

Data collection

Nonius KappaCCD diffractometer4391 independent reflections
Radiation source: fine-focus sealed tube2785 reflections with I > 2σ(I)
Monochromator: graphiteRint = 0.025
Detector resolution: 9 pixels mm-1θmax = 30.0º
T = 150(2) Kθmin = 2.7º
ω scansh = −11→11
Absorption correction: nonek = −13→12
8260 measured reflectionsl = −16→16

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.047H-atom parameters constrained
wR(F2) = 0.136  w = 1/[σ2(Fo2) + (0.0789P)2] where P = (Fo2 + 2Fc2)/3
S = 0.98(Δ/σ)max < 0.001
4391 reflectionsΔρmax = 0.29 e Å3
203 parametersΔρmin = −0.23 e Å3
76 constraintsExtinction correction: none
Primary atom site location: structure-invariant direct methods

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.
Refinement. Refinement of F^2^ against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F^2^, conventional R-factors R are based on F, with F set to zero for negative F^2^. The threshold expression of F^2^ > σ(F^2^) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F^2^ 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)

xyzUiso*/Ueq
O10.35419 (11)0.13391 (9)0.41479 (8)0.0342 (2)
O20.16009 (11)0.25274 (9)0.59974 (7)0.0302 (2)
O30.31164 (11)0.74440 (9)0.41175 (7)0.0322 (2)
O40.83171 (12)1.06354 (9)−0.08834 (8)0.0352 (2)
C10.34968 (15)0.28542 (12)0.40914 (10)0.0257 (2)
C20.24495 (14)0.34919 (12)0.50941 (9)0.0242 (2)
C30.23241 (14)0.50121 (12)0.51169 (10)0.0252 (2)
H30.16200.54410.57960.030*
C40.32276 (14)0.59219 (12)0.41457 (10)0.0242 (2)
C50.42856 (14)0.53130 (12)0.31388 (10)0.0237 (2)
C60.43875 (15)0.37648 (12)0.31392 (10)0.0260 (2)
H60.50920.33300.24630.031*
C70.52275 (15)0.62808 (13)0.21313 (10)0.0255 (2)
H70.50080.73400.21760.031*
C80.63618 (15)0.58230 (13)0.11577 (10)0.0286 (2)
H80.65830.47620.11160.034*
C110.73066 (15)0.67918 (13)0.01411 (10)0.0266 (2)
C120.72987 (14)0.83038 (13)0.01567 (10)0.0257 (2)
H120.66610.87410.08440.031*
C130.82170 (15)0.91678 (13)−0.08266 (10)0.0275 (3)
C140.91383 (17)0.85479 (15)−0.18482 (11)0.0352 (3)
H140.97540.9144−0.25240.042*
C150.91459 (18)0.70674 (15)−0.18674 (11)0.0400 (3)
H150.97700.6642−0.25620.048*
C160.82497 (17)0.61818 (14)−0.08813 (11)0.0348 (3)
H160.82810.5154−0.09060.042*
C170.48206 (17)0.05869 (13)0.32371 (12)0.0372 (3)
H17A0.44830.11270.24350.056*
H17B0.4825−0.05160.34110.056*
H17C0.60300.06340.32410.056*
C180.06092 (16)0.31142 (13)0.70597 (10)0.0303 (3)
H18A0.14280.33480.74390.046*
H18B0.00740.23190.76400.046*
H18C−0.03530.40770.68280.046*
C190.19201 (16)0.81424 (13)0.50742 (11)0.0329 (3)
H19A0.06890.81240.50970.049*
H19B0.19390.92350.49300.049*
H19C0.23090.75500.58540.049*
C200.75180 (17)1.12894 (14)0.01691 (11)0.0349 (3)
H20A0.62081.14490.03260.052*
H20B0.77621.23020.00290.052*
H20C0.80361.05660.08750.052*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
O10.0446 (5)0.0235 (4)0.0337 (5)−0.0156 (3)0.0077 (4)−0.0104 (3)
O20.0344 (4)0.0262 (4)0.0267 (4)−0.0133 (3)0.0047 (3)−0.0040 (3)
O30.0395 (5)0.0247 (4)0.0317 (4)−0.0148 (3)0.0080 (4)−0.0108 (3)
O40.0432 (5)0.0296 (4)0.0328 (5)−0.0187 (4)0.0041 (4)−0.0064 (4)
C10.0290 (6)0.0202 (5)0.0279 (6)−0.0089 (4)−0.0023 (5)−0.0054 (4)
C20.0240 (5)0.0245 (5)0.0221 (5)−0.0092 (4)−0.0019 (4)−0.0015 (4)
C30.0251 (5)0.0255 (5)0.0243 (5)−0.0078 (4)−0.0008 (4)−0.0066 (4)
C40.0256 (5)0.0212 (5)0.0264 (6)−0.0083 (4)−0.0024 (4)−0.0062 (4)
C50.0231 (5)0.0239 (5)0.0242 (5)−0.0089 (4)−0.0024 (4)−0.0040 (4)
C60.0278 (6)0.0255 (5)0.0244 (5)−0.0095 (4)0.0002 (4)−0.0069 (4)
C70.0272 (6)0.0238 (5)0.0255 (6)−0.0097 (4)−0.0024 (5)−0.0045 (4)
C80.0339 (6)0.0233 (5)0.0279 (6)−0.0116 (4)0.0006 (5)−0.0056 (4)
C110.0261 (5)0.0276 (6)0.0244 (5)−0.0091 (4)−0.0007 (4)−0.0046 (4)
C120.0259 (5)0.0282 (5)0.0217 (5)−0.0089 (4)0.0002 (4)−0.0059 (4)
C130.0274 (6)0.0281 (6)0.0266 (6)−0.0105 (5)−0.0020 (5)−0.0048 (5)
C140.0397 (7)0.0398 (7)0.0259 (6)−0.0210 (6)0.0055 (5)−0.0051 (5)
C150.0488 (8)0.0436 (7)0.0278 (6)−0.0192 (6)0.0094 (6)−0.0149 (6)
C160.0434 (7)0.0302 (6)0.0309 (6)−0.0158 (5)0.0058 (5)−0.0112 (5)
C170.0439 (7)0.0279 (6)0.0381 (7)−0.0126 (5)0.0071 (6)−0.0141 (5)
C180.0343 (6)0.0345 (6)0.0211 (5)−0.0152 (5)0.0019 (5)−0.0038 (5)
C190.0353 (6)0.0276 (6)0.0358 (7)−0.0111 (5)0.0055 (5)−0.0142 (5)
C200.0374 (7)0.0310 (6)0.0373 (7)−0.0134 (5)0.0003 (5)−0.0104 (5)

Geometric parameters (Å, °)

O1—C11.3720 (12)C11—C121.4011 (15)
O1—C171.4298 (13)C12—C131.3896 (15)
O2—C21.3670 (13)C12—H120.9500
O2—C181.4308 (13)C13—C141.3945 (16)
O3—C41.3713 (12)C14—C151.3733 (16)
O3—C191.4231 (13)C14—H140.9500
O4—C131.3677 (13)C15—C161.3927 (17)
O4—C201.4281 (13)C15—H150.9500
C1—C61.3828 (15)C16—H160.9500
C1—C21.4052 (14)C17—H17A0.9800
C2—C31.3826 (14)C17—H17B0.9800
C3—C41.3988 (15)C17—H17C0.9800
C3—H30.9500C18—H18A0.9800
C4—C51.3994 (14)C18—H18B0.9800
C5—C61.4060 (14)C18—H18C0.9800
C5—C71.4651 (15)C19—H19A0.9800
C6—H60.9500C19—H19B0.9800
C7—C81.3336 (16)C19—H19C0.9800
C7—H70.9500C20—H20A0.9800
C8—C111.4721 (15)C20—H20B0.9800
C8—H80.9500C20—H20C0.9800
C11—C161.3942 (15)
C1—O1—C17116.35 (8)O4—C13—C14115.01 (9)
C2—O2—C18117.08 (8)C12—C13—C14120.36 (10)
C4—O3—C19117.81 (8)C15—C14—C13119.33 (10)
C13—O4—C20117.84 (8)C15—C14—H14120.3
O1—C1—C6125.08 (10)C13—C14—H14120.3
O1—C1—C2115.75 (9)C14—C15—C16120.85 (11)
C6—C1—C2119.18 (9)C14—C15—H15119.6
O2—C2—C3124.25 (10)C16—C15—H15119.6
O2—C2—C1115.93 (9)C15—C16—C11120.49 (10)
C3—C2—C1119.82 (9)C15—C16—H16119.8
C2—C3—C4120.40 (10)C11—C16—H16119.8
C2—C3—H3119.8O1—C17—H17A109.5
C4—C3—H3119.8O1—C17—H17B109.5
O3—C4—C3122.49 (9)H17A—C17—H17B109.5
O3—C4—C5116.58 (9)O1—C17—H17C109.5
C3—C4—C5120.93 (9)H17A—C17—H17C109.5
C4—C5—C6117.45 (9)H17B—C17—H17C109.5
C4—C5—C7120.20 (9)O2—C18—H18A109.5
C6—C5—C7122.35 (10)O2—C18—H18B109.5
C1—C6—C5122.22 (10)H18A—C18—H18B109.5
C1—C6—H6118.9O2—C18—H18C109.5
C5—C6—H6118.9H18A—C18—H18C109.5
C8—C7—C5126.52 (10)H18B—C18—H18C109.5
C8—C7—H7116.7O3—C19—H19A109.5
C5—C7—H7116.7O3—C19—H19B109.5
C7—C8—C11126.74 (10)H19A—C19—H19B109.5
C7—C8—H8116.6O3—C19—H19C109.5
C11—C8—H8116.6H19A—C19—H19C109.5
C16—C11—C12118.51 (10)H19B—C19—H19C109.5
C16—C11—C8118.73 (10)O4—C20—H20A109.5
C12—C11—C8122.76 (10)O4—C20—H20B109.5
C13—C12—C11120.45 (10)H20A—C20—H20B109.5
C13—C12—H12119.8O4—C20—H20C109.5
C11—C12—H12119.8H20A—C20—H20C109.5
O4—C13—C12124.63 (10)H20B—C20—H20C109.5

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C7—H7···O30.952.392.7504 (14)102
C17—H17B···O3i0.982.523.4046 (16)150
C18—H18B···O4ii0.982.463.4342 (15)172
C19—H19B···O1iii0.982.513.4082 (15)152
C17—H17A···Cg2iv0.982.913.7863 (15)149
C18—H18C···Cg1v0.982.673.5578 (14)151

Symmetry codes: (i) x, y−1, z; (ii) x−1, y−1, z+1; (iii) x, y+1, z; (iv) −x+1, −y+1, −z; (v) −x, −y+1, −z+1.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: FB2091).

References

  • Anjaneyulu, A. S. R., Rani, G. S., Mallavadhani, U. V. & Murthy, Y. L. N. (1990). Indian J. Chem. Sect. B, 29, 219–223.
  • Cushman, M., Nagarathnam, D., Gopal, D., Chakraborti, A. K., Lin, C. M. & Hamel, E. (1991). J. Med. Chem.34, 2579–2588. [PubMed]
  • Krishnamurty, H. G. & Maheshwari, N. (1988). Indian J. Chem. Sect. B, 27, 1035–1036.
  • Murillo, J. (2001). Biota Colomb 2, 49–58.
  • Nakamura, H., Kuroda, H., Saito, H., Suzuki, R., Yamori, T., Maruyama, K. & Haga, T. (2006). ChemMedChem, 1, 729–740. [PubMed]
  • Nonius (1998). COLLECT Nonius BV, Delft, The Netherlands.
  • 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.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Wang, Z. W., Ma, W. W., McLaughlin, J. L. & Gupta, M. P. (1988). J. Nat. Prod.51, 382–384. [PubMed]

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