Semisynthetic roxburghin tetra-methyl ether.

The title mol-ecule, (E)-2,3',4,5-tetra-methoxy-stilbene, C(18)H(20)O(4), is virtually planar. The angle between the two benzene rings is 4.06 (6)°. The inter-molecular inter-actions present in the structure are weak. There are C-H⋯O hydrogen bonds and C-H⋯π-electron ring inter-actions. The mol-ecules are ordered into planes that are parallel to (01). The distance between adjacent planes is about 3.3 Å and therefore π-π electron inter-actions 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

C18H20O4

M = 300.34

Triclinic,

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 ▶); cell refinement: 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.

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

C18H20O4	Z = 2
Mr = 300.34	F000 = 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 = 1.0–30.0º
c = 11.6194 (5) Å	µ = 0.09 mm−1
α = 73.400 (2)º	T = 150 (2) K
β = 75.479 (3)º	Needle, yellow
γ = 70.335 (2)º	0.35 × 0.10 × 0.04 mm
V = 760.59 (7) Å3

Nonius KappaCCD diffractometer	4391 independent reflections
Radiation source: fine-focus sealed tube	2785 reflections with I > 2σ(I)
Monochromator: graphite	Rint = 0.025
Detector resolution: 9 pixels mm-1	θmax = 30.0º
T = 150(2) K	θmin = 2.7º
ω scans	h = −11→11
Absorption correction: none	k = −13→12
8260 measured reflections	l = −16→16

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.047	H-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 reflections	Δρmax = 0.29 e Å−3
203 parameters	Δρmin = −0.23 e Å−3
76 constraints	Extinction correction: none
Primary atom site location: structure-invariant direct methods

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

Table 1

Hydrogen-bond geometry (Å, °)

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) ; (ii) ; (iii) ; (iv) ; (v) . Cg1 is the centroid of the C1–C6 ring and Cg2 is the centroid of the C11–C16 ring.