organic compounds
Semisynthetic roxburghin tetramethyl ether
aInstituto de Química, Química de Plantas Colombianas, Universidad de Antioquia, AA 1226, Medellín, Colombia, bGrupo de Procesos Ambientales y Biotecnológicos, Departamento de Ingeniería de Procesos, Universidad EAFIT, AA 3300, Medellín, Colombia, cDepartamento de Química Orgánica, Universidad de Valencia, E-46100 Valencia, Spain, and dDepartamento de Farmacología, Facultad de Farmacia, Universidad de Valencia, Burjassot, Valencia, Spain
*Correspondence e-mail: asaez@eafit.edu.co
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 (01). 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); Nakamura et al. (2006). For the precursors of the title compound, see: Krishnamurty & Maheshwari (1988); Anjaneyulu et al. (1990); Wang et al. (1988); Murillo (2001).
Experimental
Crystal data
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Data collection
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Refinement
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Data collection: COLLECT (Nonius, 1998); cell SCALEPACK (Otwinowski & Minor, 1997); data reduction: SCALEPACK; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL/PC (Sheldrick, 2008); software used to prepare material for publication: SHELXL97.
Supporting information
10.1107/S1600536808018266/fb2091sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536808018266/fb2091Isup2.hkl
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
with silica gel using hexane/ethylacetate 9:1 as an 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).
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).
Data collection: COLLECT (Nonius, 1998); cell
SCALEPACK (Otwinowski & Minor, 1997); data reduction: SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL/PC (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).Fig. 1. The title molecule with the displacement ellipsoids shown at the 50% probability level. |
C18H20O4 | Z = 2 |
Mr = 300.34 | F(000) = 320 |
Triclinic, P1 | Dx = 1.311 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 7.9633 (4) Å | Cell parameters from 46078 reflections |
b = 9.2454 (5) Å | θ = 1.0–30.0° |
c = 11.6194 (5) Å | µ = 0.09 mm−1 |
α = 73.400 (2)° | T = 150 K |
β = 75.479 (3)° | Needle, yellow |
γ = 70.335 (2)° | 0.35 × 0.10 × 0.04 mm |
V = 760.59 (7) Å3 |
Nonius KappaCCD diffractometer | 2785 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.025 |
Graphite monochromator | θmax = 30.0°, θmin = 2.7° |
Detector resolution: 9 pixels mm-1 | h = −11→11 |
ω scans | k = −13→12 |
8260 measured reflections | l = −16→16 |
4391 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: difference Fourier map |
wR(F2) = 0.136 | H-atom parameters constrained |
S = 0.98 | w = 1/[σ2(Fo2) + (0.0789P)2] where P = (Fo2 + 2Fc2)/3 |
4391 reflections | (Δ/σ)max < 0.001 |
203 parameters | Δρmax = 0.29 e Å−3 |
0 restraints | Δρmin = −0.23 e Å−3 |
76 constraints |
C18H20O4 | γ = 70.335 (2)° |
Mr = 300.34 | V = 760.59 (7) Å3 |
Triclinic, P1 | Z = 2 |
a = 7.9633 (4) Å | Mo Kα radiation |
b = 9.2454 (5) Å | µ = 0.09 mm−1 |
c = 11.6194 (5) Å | T = 150 K |
α = 73.400 (2)° | 0.35 × 0.10 × 0.04 mm |
β = 75.479 (3)° |
Nonius KappaCCD diffractometer | 2785 reflections with I > 2σ(I) |
8260 measured reflections | Rint = 0.025 |
4391 independent reflections |
R[F2 > 2σ(F2)] = 0.047 | 0 restraints |
wR(F2) = 0.136 | H-atom parameters constrained |
S = 0.98 | Δρmax = 0.29 e Å−3 |
4391 reflections | Δρmin = −0.23 e Å−3 |
203 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 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. |
x | y | z | Uiso*/Ueq | ||
O1 | 0.35419 (11) | 0.13391 (9) | 0.41479 (8) | 0.0342 (2) | |
O2 | 0.16009 (11) | 0.25274 (9) | 0.59974 (7) | 0.0302 (2) | |
O3 | 0.31164 (11) | 0.74440 (9) | 0.41175 (7) | 0.0322 (2) | |
O4 | 0.83171 (12) | 1.06354 (9) | −0.08834 (8) | 0.0352 (2) | |
C1 | 0.34968 (15) | 0.28542 (12) | 0.40914 (10) | 0.0257 (2) | |
C2 | 0.24495 (14) | 0.34919 (12) | 0.50941 (9) | 0.0242 (2) | |
C3 | 0.23241 (14) | 0.50121 (12) | 0.51169 (10) | 0.0252 (2) | |
H3 | 0.1620 | 0.5441 | 0.5796 | 0.030* | |
C4 | 0.32276 (14) | 0.59219 (12) | 0.41457 (10) | 0.0242 (2) | |
C5 | 0.42856 (14) | 0.53130 (12) | 0.31388 (10) | 0.0237 (2) | |
C6 | 0.43875 (15) | 0.37648 (12) | 0.31392 (10) | 0.0260 (2) | |
H6 | 0.5092 | 0.3330 | 0.2463 | 0.031* | |
C7 | 0.52275 (15) | 0.62808 (13) | 0.21313 (10) | 0.0255 (2) | |
H7 | 0.5008 | 0.7340 | 0.2176 | 0.031* | |
C8 | 0.63618 (15) | 0.58230 (13) | 0.11577 (10) | 0.0286 (2) | |
H8 | 0.6583 | 0.4762 | 0.1116 | 0.034* | |
C11 | 0.73066 (15) | 0.67918 (13) | 0.01411 (10) | 0.0266 (2) | |
C12 | 0.72987 (14) | 0.83038 (13) | 0.01567 (10) | 0.0257 (2) | |
H12 | 0.6661 | 0.8741 | 0.0844 | 0.031* | |
C13 | 0.82170 (15) | 0.91678 (13) | −0.08266 (10) | 0.0275 (3) | |
C14 | 0.91383 (17) | 0.85479 (15) | −0.18482 (11) | 0.0352 (3) | |
H14 | 0.9754 | 0.9144 | −0.2524 | 0.042* | |
C15 | 0.91459 (18) | 0.70674 (15) | −0.18674 (11) | 0.0400 (3) | |
H15 | 0.9770 | 0.6642 | −0.2562 | 0.048* | |
C16 | 0.82497 (17) | 0.61818 (14) | −0.08813 (11) | 0.0348 (3) | |
H16 | 0.8281 | 0.5154 | −0.0906 | 0.042* | |
C17 | 0.48206 (17) | 0.05869 (13) | 0.32371 (12) | 0.0372 (3) | |
H17A | 0.4483 | 0.1127 | 0.2435 | 0.056* | |
H17B | 0.4825 | −0.0516 | 0.3411 | 0.056* | |
H17C | 0.6030 | 0.0634 | 0.3241 | 0.056* | |
C18 | 0.06092 (16) | 0.31142 (13) | 0.70597 (10) | 0.0303 (3) | |
H18A | 0.1428 | 0.3348 | 0.7439 | 0.046* | |
H18B | 0.0074 | 0.2319 | 0.7640 | 0.046* | |
H18C | −0.0353 | 0.4077 | 0.6828 | 0.046* | |
C19 | 0.19201 (16) | 0.81424 (13) | 0.50742 (11) | 0.0329 (3) | |
H19A | 0.0689 | 0.8124 | 0.5097 | 0.049* | |
H19B | 0.1939 | 0.9235 | 0.4930 | 0.049* | |
H19C | 0.2309 | 0.7550 | 0.5854 | 0.049* | |
C20 | 0.75180 (17) | 1.12894 (14) | 0.01691 (11) | 0.0349 (3) | |
H20A | 0.6208 | 1.1449 | 0.0326 | 0.052* | |
H20B | 0.7762 | 1.2302 | 0.0029 | 0.052* | |
H20C | 0.8036 | 1.0566 | 0.0875 | 0.052* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0446 (5) | 0.0235 (4) | 0.0337 (5) | −0.0156 (3) | 0.0077 (4) | −0.0104 (3) |
O2 | 0.0344 (4) | 0.0262 (4) | 0.0267 (4) | −0.0133 (3) | 0.0047 (3) | −0.0040 (3) |
O3 | 0.0395 (5) | 0.0247 (4) | 0.0317 (4) | −0.0148 (3) | 0.0080 (4) | −0.0108 (3) |
O4 | 0.0432 (5) | 0.0296 (4) | 0.0328 (5) | −0.0187 (4) | 0.0041 (4) | −0.0064 (4) |
C1 | 0.0290 (6) | 0.0202 (5) | 0.0279 (6) | −0.0089 (4) | −0.0023 (5) | −0.0054 (4) |
C2 | 0.0240 (5) | 0.0245 (5) | 0.0221 (5) | −0.0092 (4) | −0.0019 (4) | −0.0015 (4) |
C3 | 0.0251 (5) | 0.0255 (5) | 0.0243 (5) | −0.0078 (4) | −0.0008 (4) | −0.0066 (4) |
C4 | 0.0256 (5) | 0.0212 (5) | 0.0264 (6) | −0.0083 (4) | −0.0024 (4) | −0.0062 (4) |
C5 | 0.0231 (5) | 0.0239 (5) | 0.0242 (5) | −0.0089 (4) | −0.0024 (4) | −0.0040 (4) |
C6 | 0.0278 (6) | 0.0255 (5) | 0.0244 (5) | −0.0095 (4) | 0.0002 (4) | −0.0069 (4) |
C7 | 0.0272 (6) | 0.0238 (5) | 0.0255 (6) | −0.0097 (4) | −0.0024 (5) | −0.0045 (4) |
C8 | 0.0339 (6) | 0.0233 (5) | 0.0279 (6) | −0.0116 (4) | 0.0006 (5) | −0.0056 (4) |
C11 | 0.0261 (5) | 0.0276 (6) | 0.0244 (5) | −0.0091 (4) | −0.0007 (4) | −0.0046 (4) |
C12 | 0.0259 (5) | 0.0282 (5) | 0.0217 (5) | −0.0089 (4) | 0.0002 (4) | −0.0059 (4) |
C13 | 0.0274 (6) | 0.0281 (6) | 0.0266 (6) | −0.0105 (5) | −0.0020 (5) | −0.0048 (5) |
C14 | 0.0397 (7) | 0.0398 (7) | 0.0259 (6) | −0.0210 (6) | 0.0055 (5) | −0.0051 (5) |
C15 | 0.0488 (8) | 0.0436 (7) | 0.0278 (6) | −0.0192 (6) | 0.0094 (6) | −0.0149 (6) |
C16 | 0.0434 (7) | 0.0302 (6) | 0.0309 (6) | −0.0158 (5) | 0.0058 (5) | −0.0112 (5) |
C17 | 0.0439 (7) | 0.0279 (6) | 0.0381 (7) | −0.0126 (5) | 0.0071 (6) | −0.0141 (5) |
C18 | 0.0343 (6) | 0.0345 (6) | 0.0211 (5) | −0.0152 (5) | 0.0019 (5) | −0.0038 (5) |
C19 | 0.0353 (6) | 0.0276 (6) | 0.0358 (7) | −0.0111 (5) | 0.0055 (5) | −0.0142 (5) |
C20 | 0.0374 (7) | 0.0310 (6) | 0.0373 (7) | −0.0134 (5) | 0.0003 (5) | −0.0104 (5) |
O1—C1 | 1.3720 (12) | C11—C12 | 1.4011 (15) |
O1—C17 | 1.4298 (13) | C12—C13 | 1.3896 (15) |
O2—C2 | 1.3670 (13) | C12—H12 | 0.9500 |
O2—C18 | 1.4308 (13) | C13—C14 | 1.3945 (16) |
O3—C4 | 1.3713 (12) | C14—C15 | 1.3733 (16) |
O3—C19 | 1.4231 (13) | C14—H14 | 0.9500 |
O4—C13 | 1.3677 (13) | C15—C16 | 1.3927 (17) |
O4—C20 | 1.4281 (13) | C15—H15 | 0.9500 |
C1—C6 | 1.3828 (15) | C16—H16 | 0.9500 |
C1—C2 | 1.4052 (14) | C17—H17A | 0.9800 |
C2—C3 | 1.3826 (14) | C17—H17B | 0.9800 |
C3—C4 | 1.3988 (15) | C17—H17C | 0.9800 |
C3—H3 | 0.9500 | C18—H18A | 0.9800 |
C4—C5 | 1.3994 (14) | C18—H18B | 0.9800 |
C5—C6 | 1.4060 (14) | C18—H18C | 0.9800 |
C5—C7 | 1.4651 (15) | C19—H19A | 0.9800 |
C6—H6 | 0.9500 | C19—H19B | 0.9800 |
C7—C8 | 1.3336 (16) | C19—H19C | 0.9800 |
C7—H7 | 0.9500 | C20—H20A | 0.9800 |
C8—C11 | 1.4721 (15) | C20—H20B | 0.9800 |
C8—H8 | 0.9500 | C20—H20C | 0.9800 |
C11—C16 | 1.3942 (15) | ||
C1—O1—C17 | 116.35 (8) | O4—C13—C14 | 115.01 (9) |
C2—O2—C18 | 117.08 (8) | C12—C13—C14 | 120.36 (10) |
C4—O3—C19 | 117.81 (8) | C15—C14—C13 | 119.33 (10) |
C13—O4—C20 | 117.84 (8) | C15—C14—H14 | 120.3 |
O1—C1—C6 | 125.08 (10) | C13—C14—H14 | 120.3 |
O1—C1—C2 | 115.75 (9) | C14—C15—C16 | 120.85 (11) |
C6—C1—C2 | 119.18 (9) | C14—C15—H15 | 119.6 |
O2—C2—C3 | 124.25 (10) | C16—C15—H15 | 119.6 |
O2—C2—C1 | 115.93 (9) | C15—C16—C11 | 120.49 (10) |
C3—C2—C1 | 119.82 (9) | C15—C16—H16 | 119.8 |
C2—C3—C4 | 120.40 (10) | C11—C16—H16 | 119.8 |
C2—C3—H3 | 119.8 | O1—C17—H17A | 109.5 |
C4—C3—H3 | 119.8 | O1—C17—H17B | 109.5 |
O3—C4—C3 | 122.49 (9) | H17A—C17—H17B | 109.5 |
O3—C4—C5 | 116.58 (9) | O1—C17—H17C | 109.5 |
C3—C4—C5 | 120.93 (9) | H17A—C17—H17C | 109.5 |
C4—C5—C6 | 117.45 (9) | H17B—C17—H17C | 109.5 |
C4—C5—C7 | 120.20 (9) | O2—C18—H18A | 109.5 |
C6—C5—C7 | 122.35 (10) | O2—C18—H18B | 109.5 |
C1—C6—C5 | 122.22 (10) | H18A—C18—H18B | 109.5 |
C1—C6—H6 | 118.9 | O2—C18—H18C | 109.5 |
C5—C6—H6 | 118.9 | H18A—C18—H18C | 109.5 |
C8—C7—C5 | 126.52 (10) | H18B—C18—H18C | 109.5 |
C8—C7—H7 | 116.7 | O3—C19—H19A | 109.5 |
C5—C7—H7 | 116.7 | O3—C19—H19B | 109.5 |
C7—C8—C11 | 126.74 (10) | H19A—C19—H19B | 109.5 |
C7—C8—H8 | 116.6 | O3—C19—H19C | 109.5 |
C11—C8—H8 | 116.6 | H19A—C19—H19C | 109.5 |
C16—C11—C12 | 118.51 (10) | H19B—C19—H19C | 109.5 |
C16—C11—C8 | 118.73 (10) | O4—C20—H20A | 109.5 |
C12—C11—C8 | 122.76 (10) | O4—C20—H20B | 109.5 |
C13—C12—C11 | 120.45 (10) | H20A—C20—H20B | 109.5 |
C13—C12—H12 | 119.8 | O4—C20—H20C | 109.5 |
C11—C12—H12 | 119.8 | H20A—C20—H20C | 109.5 |
O4—C13—C12 | 124.63 (10) | H20B—C20—H20C | 109.5 |
D—H···A | D—H | H···A | D···A | D—H···A |
C7—H7···O3 | 0.95 | 2.39 | 2.7504 (14) | 102 |
C17—H17B···O3i | 0.98 | 2.52 | 3.4046 (16) | 150 |
C18—H18B···O4ii | 0.98 | 2.46 | 3.4342 (15) | 172 |
C19—H19B···O1iii | 0.98 | 2.51 | 3.4082 (15) | 152 |
C17—H17A···Cg2iv | 0.98 | 2.91 | 3.7863 (15) | 149 |
C18—H18C···Cg1v | 0.98 | 2.67 | 3.5578 (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. |
Experimental details
Crystal data | |
Chemical formula | C18H20O4 |
Mr | 300.34 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 150 |
a, b, c (Å) | 7.9633 (4), 9.2454 (5), 11.6194 (5) |
α, β, γ (°) | 73.400 (2), 75.479 (3), 70.335 (2) |
V (Å3) | 760.59 (7) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.35 × 0.10 × 0.04 |
Data collection | |
Diffractometer | Nonius KappaCCD diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 8260, 4391, 2785 |
Rint | 0.025 |
(sin θ/λ)max (Å−1) | 0.704 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.047, 0.136, 0.98 |
No. of reflections | 4391 |
No. of parameters | 203 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.29, −0.23 |
Computer programs: COLLECT (Nonius, 1998), SCALEPACK (Otwinowski & Minor, 1997), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL/PC (Sheldrick, 2008).
D—H···A | D—H | H···A | D···A | D—H···A |
C7—H7···O3 | 0.95 | 2.39 | 2.7504 (14) | 102 |
C17—H17B···O3i | 0.98 | 2.52 | 3.4046 (16) | 150 |
C18—H18B···O4ii | 0.98 | 2.46 | 3.4342 (15) | 172 |
C19—H19B···O1iii | 0.98 | 2.51 | 3.4082 (15) | 152 |
C17—H17A···Cg2iv | 0.98 | 2.91 | 3.7863 (15) | 149 |
C18—H18C···Cg1v | 0.98 | 2.67 | 3.5578 (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. |
Acknowledgements
The authors thank Colciencias and Universidad de Antioquia (Programa de Sostenibilidad) for financial support.
References
Anjaneyulu, A. S. R., Rani, G. S., Mallavadhani, U. V. & Murthy, Y. L. N. (1990). Indian J. Chem. Sect. B, 29, 219–223. Google Scholar
Cushman, M., Nagarathnam, D., Gopal, D., Chakraborti, A. K., Lin, C. M. & Hamel, E. (1991). J. Med. Chem. 34, 2579–2588. CrossRef PubMed CAS Web of Science Google Scholar
Krishnamurty, H. G. & Maheshwari, N. (1988). Indian J. Chem. Sect. B, 27, 1035–1036. Google Scholar
Murillo, J. (2001). Biota Colomb. 2, 49–58. Google Scholar
Nakamura, H., Kuroda, H., Saito, H., Suzuki, R., Yamori, T., Maruyama, K. & Haga, T. (2006). ChemMedChem, 1, 729–740. Web of Science CrossRef PubMed CAS Google Scholar
Nonius (1998). COLLECT. Nonius BV, Delft, The Netherlands. Google Scholar
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. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Wang, Z. W., Ma, W. W., McLaughlin, J. L. & Gupta, M. P. (1988). J. Nat. Prod. 51, 382–384. CrossRef CAS PubMed Web of Science Google Scholar
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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).