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The title compound, C19H21ClO4, adopts a non-planar conformation. The angle between the aromatic ring planes is 75.74 (6)°. The angle between the plane of the aromatic ring attached to the C atom carrying the chloro­methyl substituent and the plane defined by the ethyl­ene group and the atoms attached to it is 40.60 (6)°. The angle between this latter plane and the plane of the second aromatic ring is 35.29 (6)°. The arrangement of the mol­ecules in the crystal lattice can be attributed to weak C—H...O and C—H...Cl hydrogen bonding. Stereoisomers of methyl 2,3-bis(4-acetoxy-3-methoxy­phenyl)-2-propene­sulfonate are assigned, based on 1H NMR spectral comparisons with the title compound and the isomeric E form.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536803006536/lh6052sup1.cif
Contains datablocks Ib, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S1600536803006536/lh6052Ibsup2.hkl
Contains datablock Ib

CCDC reference: 209995

Key indicators

  • Single-crystal X-ray study
  • T = 173 K
  • Mean [sigma](C-C) = 0.002 Å
  • R factor = 0.038
  • wR factor = 0.113
  • Data-to-parameter ratio = 23.8

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry








Comment top

Stereoisomers of α-chloromethyl-3,3',4,4'-tetramethoxystilbene, (I), are present in reaction mixtures obtained on refluxing of the lignin model 1,2-bis(3,4-dimethoxyphenyl)-1,3-propanediol with 0.2 M hydrogen chloride in dioxane–water 9:1 (Li et al., 1997). The identification of the compounds was based on comparisons with synthetic samples (Li et al., 1997). The synthetic method applied gave a mixture of stereoisomers from which the Z isomer, (Ib), could be isolated in crystalline form (Li et al., 1997). The crystalline form of the E isomer, (Ia), has been described earlier (Russel & Hunziker, 1969). To verify the steric assignments of the E, (Ia), and Z, (Ib), isomers of (I), we have determined the crystal structure of (Ib).

A perspective drawing of (Ib) and the atom-numbering scheme is shown in Fig. 1. In the crystal structure, (Ib) adopts a non-planar conformation. The torsion angles C2—C1—C7—C8 and C7—C8—C11—C12 are 32.84 (16) and 41.63 (14)°, respectively. The angle between the aromatic ring planes is 75.74 (6)°. The ethylene group and the atoms attached to it (C1, C11 and C19) are nearly coplanar [maximum deviation 0.028 (1) Å]. The angles between the least-squares plane and the aromatic ring planes C1–C6 and C11–C16 are 35.29 (6) and 40.60 (6)°, respectively. The conformations of the α-substituted stilbenes (Z)-2,3-bis(3,4-dimethoxyphenyl)-2-propen-1-ol (Stomberg et al., 1995) and methyl (E)-p-[2-(2,3-dihydro-3,3-dimethyl-5-benzofuranyl)-1-propenyl]benzoate (Gale et al., 1990) exhibit similarities to that of (Ib). Stilbenes with trans-orientated aryl groups lacking an α-substituent, such as (E)-4,4'-dimethoxystilbene (Theocharis et al., 1984), are planar or nearly planar.

There are weak C—H···O and C—H···Cl hydrogen bonds present in the crystal structure of (Ib) (Table 1). There are two C–H···O hydrogen bonds formed by dimers of molecules related by an inversion center (Fig. 2). On the first-level graph-set, following Bernstein et al. (1995) and Grell et al. (1999), the hydrogen bond C12–H12···O1i [symmetry code: (i) 1 − x, 1 − y,-z] forms an R22(18) ring, and the hydrogen bond C17–H17C···O2i forms an R22(26) ring. The intramolecular hydrogen bond C2–H2···Cl1 forms an S(7) string, while the intermolecular hydrogen bond C17–H17B···Cl1ii [symmetry code: (ii) x, 1 + y, z] forms a C(9) chain, connecting the molecules in the b direction (Fig. 3). On the second-level graph-set, rings R22(10), R22(22), R44(24), R44(28), R44(36) and R44(44) were recognized. The assignment of graph-set descriptors were performed using PLUTO, as described by Motherwell et al. (1999).

The methylene group signal is located at δ 4.44 in the 1H NMR spectrum of the E isomer, (Ia), and at δ 4.65 in the 1H NMR spectrum of Z isomer, (Ib) (Li et al. 1997). The methylene group signal of the E isomer, (IIa) (δ 4.89), is also located at higher field than that of the Z isomer, (IIb) (δ 5.16) (Li et al. 1997). Stereoisomers of (III) have been described by Gellerstedt et al. (1976) but steric assignments were not reported. Based on 1H NMR spectral comparisons with (I) and (II) it is possible to conclude that the isomer denoted `1. Form' by Gellerstedt et al. (1976) is (IIIb) (the methylene group signal is located at δ 4.46) and that the isomer denoted `2. Form' by these authors is (IIIa) (the methylene group signal is located at δ 4.16).

Experimental top

(Z)-α-Chloromethyl-3,3',4,4'-tetramethoxystilbene, (Ib), was prepared according to Li et al. (1997).

Refinement top

H atoms were refined isotropically (?) and were constrained to the ideal geometry using an appropriate riding model. For methyl groups, the C—H distances (0.98 Å) and C—C—H angles (109.5°) were kept fixed, while the torsion angles were allowed to refine with the starting position based on the threefold averaged circular Fourier synthesis.

Computing details top

Data collection: SMART (Siemens, 1995); cell refinement: SAINT (Siemens, 1995); data reduction: SAINT and SADABS (Sheldrick, 2002); program(s) used to solve structure: SHELXTL (Bruker, 1997); program(s) used to refine structure: SHELXTL; molecular graphics: DIAMOND (Brandenburg, 2000); software used to prepare material for publication: SHELXTL.

Figures top
[Figure 1] Fig. 1. A perspective drawing of (Ib), showing the atom-numbering. Displacement ellipsoids are shown at the 50% probability level.
[Figure 2] Fig. 2. A centrosymmetric dimer of (Ib) formed by weak hydrogen bonds.
[Figure 3] Fig. 3. A chain of (Ib) molecules, related by unit-cell translations in the b direction, connected by weak hydrogen bonds which are shown as dashed lines.
(Z)-α-Chloromethyl-3,3'4,4'-tetramethoxystilbene top
Crystal data top
C19H21ClO4Z = 2
Mr = 348.81F(000) = 368
Triclinic, P1Dx = 1.318 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 9.2561 (1) ÅCell parameters from 5499 reflections
b = 10.0669 (2) Åθ = 2.4–31.5°
c = 11.5351 (2) ŵ = 0.24 mm1
α = 104.620 (1)°T = 173 K
β = 108.441 (1)°Prism, colourless
γ = 109.692 (1)°0.52 × 0.40 × 0.18 mm
V = 879.06 (3) Å3
Data collection top
Siemens SMART CCD area-detector
diffractometer
5768 independent reflections
Radiation source: fine-focus sealed tube4859 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.022
ω scansθmax = 31.5°, θmin = 2.4°
Absorption correction: multi-scan
(SADABS; Sheldrick, 2002)
h = 1313
Tmin = 0.887, Tmax = 0.959k = 1414
14932 measured reflectionsl = 1616
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.038Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.113H-atom parameters constrained
S = 1.02 w = 1/[σ2(Fo2) + (0.0623P)2 + 0.1791P]
where P = (Fo2 + 2Fc2)/3
5768 reflections(Δ/σ)max = 0.001
242 parametersΔρmax = 0.43 e Å3
0 restraintsΔρmin = 0.38 e Å3
Crystal data top
C19H21ClO4γ = 109.692 (1)°
Mr = 348.81V = 879.06 (3) Å3
Triclinic, P1Z = 2
a = 9.2561 (1) ÅMo Kα radiation
b = 10.0669 (2) ŵ = 0.24 mm1
c = 11.5351 (2) ÅT = 173 K
α = 104.620 (1)°0.52 × 0.40 × 0.18 mm
β = 108.441 (1)°
Data collection top
Siemens SMART CCD area-detector
diffractometer
5768 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2002)
4859 reflections with I > 2σ(I)
Tmin = 0.887, Tmax = 0.959Rint = 0.022
14932 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0380 restraints
wR(F2) = 0.113H-atom parameters constrained
S = 1.02Δρmax = 0.43 e Å3
5768 reflectionsΔρmin = 0.38 e Å3
242 parameters
Special details top

Experimental. Data were collected at low temperature using a Siemens SMART CCD diffractometer equiped with a LT-2 device. A full sphere of reciprocal space was scanned by 0.3° steps in ω with a crystal–to–detector distance of 3.97 cm, 15 s per frame. Preliminary orientation matrix was obtained from the first 100 frames using SMART (Siemens, 1995). The collected frames were integrated using the preliminary orientation matrix which was updated every 100 frames. Final cell parameters were obtained by refinement on the position of 5499 reflections with I>10σ(I) after integration of all the frames data using SAINT (Siemens, 1995).

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Cl10.92631 (4)0.58547 (3)0.29928 (3)0.03820 (9)
O10.38829 (10)0.13893 (9)0.07825 (7)0.02986 (16)
O20.25151 (10)0.05992 (9)0.33347 (7)0.03185 (17)
O31.14109 (11)1.24560 (9)0.28478 (9)0.03629 (19)
O41.46113 (10)1.31097 (9)0.38519 (9)0.03753 (19)
C10.66936 (13)0.49354 (11)0.09105 (10)0.02477 (18)
C20.60024 (12)0.39023 (11)0.03790 (9)0.02422 (18)
H20.64980.41870.05580.031 (3)*
C30.46082 (12)0.24764 (11)0.12089 (9)0.02293 (17)
C40.38404 (12)0.20478 (11)0.26015 (9)0.02408 (18)
C50.44691 (13)0.30871 (12)0.31246 (10)0.02774 (19)
H50.39370.28210.40570.042 (4)*
C60.58815 (13)0.45226 (12)0.22848 (10)0.02774 (19)
H60.62950.52270.26530.039 (4)*
C70.82139 (13)0.64411 (11)0.00837 (10)0.02652 (19)
H70.82200.72340.03900.031 (3)*
C80.96001 (13)0.68578 (11)0.10461 (10)0.02549 (18)
C90.47107 (17)0.17140 (14)0.06002 (11)0.0368 (2)
H9A0.58990.19040.08480.052 (5)*
H9B0.41150.08330.07730.050 (4)*
H9C0.46870.26290.11300.038 (4)*
C100.1916 (2)0.00466 (16)0.47466 (12)0.0501 (4)
H10A0.14470.06880.50790.066 (6)*
H10B0.10220.10220.51650.072 (6)*
H10C0.28670.00940.49670.055 (5)*
C111.09651 (12)0.84807 (11)0.17693 (10)0.02483 (18)
C121.05068 (12)0.96931 (11)0.19178 (10)0.02496 (18)
H120.93340.94650.15410.027 (3)*
C131.17530 (13)1.12196 (11)0.26097 (10)0.02643 (19)
C141.34966 (13)1.15711 (12)0.31643 (10)0.0282 (2)
C151.39521 (13)1.03838 (13)0.30004 (11)0.0308 (2)
H151.51261.06140.33540.048 (4)*
C161.26938 (13)0.88464 (12)0.23169 (11)0.0298 (2)
H161.30230.80430.22260.034 (4)*
C170.96556 (17)1.21325 (14)0.22613 (16)0.0440 (3)
H17A0.91881.16590.12870.058 (5)*
H17B0.95631.30940.25280.065 (5)*
H17C0.90121.14240.25660.046 (4)*
C181.63877 (16)1.35314 (16)0.44955 (14)0.0472 (3)
H18A1.65771.30220.51100.048 (4)*
H18B1.70331.46510.49960.075 (6)*
H18C1.67741.32100.38230.062 (5)*
C190.98628 (14)0.57325 (12)0.16213 (11)0.0295 (2)
H19A1.10790.59500.19490.043 (4)*
H19B0.91640.46750.09160.036 (4)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cl10.05197 (18)0.02781 (13)0.03007 (14)0.01506 (12)0.01622 (12)0.01111 (10)
O10.0320 (4)0.0281 (3)0.0241 (3)0.0063 (3)0.0128 (3)0.0120 (3)
O20.0305 (4)0.0270 (4)0.0221 (3)0.0016 (3)0.0087 (3)0.0056 (3)
O30.0330 (4)0.0193 (3)0.0481 (5)0.0079 (3)0.0128 (4)0.0130 (3)
O40.0278 (4)0.0269 (4)0.0378 (4)0.0009 (3)0.0055 (3)0.0131 (3)
C10.0254 (4)0.0208 (4)0.0267 (4)0.0096 (3)0.0121 (4)0.0077 (3)
C20.0251 (4)0.0231 (4)0.0215 (4)0.0091 (3)0.0107 (3)0.0064 (3)
C30.0238 (4)0.0226 (4)0.0230 (4)0.0096 (3)0.0122 (3)0.0089 (3)
C40.0229 (4)0.0229 (4)0.0227 (4)0.0081 (3)0.0096 (3)0.0074 (3)
C50.0278 (4)0.0295 (5)0.0236 (4)0.0107 (4)0.0101 (4)0.0118 (4)
C60.0290 (5)0.0256 (4)0.0288 (5)0.0110 (4)0.0126 (4)0.0135 (4)
C70.0279 (4)0.0208 (4)0.0291 (5)0.0093 (3)0.0135 (4)0.0086 (3)
C80.0266 (4)0.0205 (4)0.0287 (4)0.0104 (3)0.0138 (4)0.0074 (3)
C90.0465 (6)0.0367 (6)0.0250 (5)0.0145 (5)0.0155 (5)0.0156 (4)
C100.0513 (8)0.0411 (7)0.0227 (5)0.0034 (6)0.0091 (5)0.0032 (5)
C110.0240 (4)0.0223 (4)0.0260 (4)0.0085 (3)0.0120 (3)0.0081 (3)
C120.0229 (4)0.0209 (4)0.0273 (4)0.0069 (3)0.0101 (3)0.0096 (3)
C130.0272 (4)0.0211 (4)0.0277 (4)0.0069 (3)0.0113 (4)0.0115 (3)
C140.0255 (4)0.0256 (4)0.0253 (4)0.0031 (4)0.0096 (4)0.0116 (4)
C150.0223 (4)0.0347 (5)0.0312 (5)0.0082 (4)0.0119 (4)0.0135 (4)
C160.0261 (5)0.0296 (5)0.0332 (5)0.0123 (4)0.0142 (4)0.0111 (4)
C170.0375 (6)0.0260 (5)0.0690 (9)0.0155 (5)0.0212 (6)0.0212 (6)
C180.0262 (5)0.0436 (7)0.0430 (7)0.0028 (5)0.0071 (5)0.0105 (6)
C190.0303 (5)0.0230 (4)0.0345 (5)0.0138 (4)0.0133 (4)0.0095 (4)
Geometric parameters (Å, º) top
Cl1—C191.8246 (12)C9—H9A0.9800
O1—C31.3696 (11)C9—H9B0.9800
O1—C91.4257 (13)C9—H9C0.9800
O2—C41.3646 (11)C10—H10A0.9800
O2—C101.4257 (14)C10—H10B0.9800
O3—C131.3686 (13)C10—H10C0.9800
O3—C171.4284 (15)C11—C161.3932 (14)
O4—C141.3703 (12)C11—C121.4102 (14)
O4—C181.4259 (16)C12—C131.3903 (13)
C1—C61.3978 (14)C12—H120.9500
C1—C21.4102 (13)C13—C141.4096 (15)
C1—C71.4735 (13)C14—C151.3850 (16)
C2—C31.3851 (13)C15—C161.4006 (15)
C2—H20.9500C15—H150.9500
C3—C41.4118 (13)C16—H160.9500
C4—C51.3884 (14)C17—H17A0.9800
C5—C61.3982 (14)C17—H17B0.9800
C5—H50.9500C17—H17C0.9800
C6—H60.9500C18—H18A0.9800
C7—C81.3507 (14)C18—H18B0.9800
C7—H70.9500C18—H18C0.9800
C8—C111.4885 (13)C19—H19A0.9900
C8—C191.4985 (14)C19—H19B0.9900
C3—O1—C9117.06 (8)H10A—C10—H10C109.5
C4—O2—C10116.49 (9)H10B—C10—H10C109.5
C13—O3—C17116.71 (8)C16—C11—C12118.56 (9)
C14—O4—C18117.65 (10)C16—C11—C8122.03 (9)
C6—C1—C2118.44 (9)C12—C11—C8119.41 (9)
C6—C1—C7118.40 (9)C13—C12—C11120.69 (9)
C2—C1—C7123.15 (9)C13—C12—H12119.7
C3—C2—C1120.70 (9)C11—C12—H12119.7
C3—C2—H2119.6O3—C13—C12124.19 (9)
C1—C2—H2119.6O3—C13—C14115.67 (9)
O1—C3—C2124.59 (8)C12—C13—C14120.09 (9)
O1—C3—C4115.14 (8)O4—C14—C15125.49 (10)
C2—C3—C4120.27 (8)O4—C14—C13115.14 (10)
O2—C4—C5125.05 (9)C15—C14—C13119.37 (9)
O2—C4—C3115.69 (8)C14—C15—C16120.43 (9)
C5—C4—C3119.26 (9)C14—C15—H15119.8
C4—C5—C6120.30 (9)C16—C15—H15119.8
C4—C5—H5119.8C11—C16—C15120.85 (10)
C6—C5—H5119.8C11—C16—H16119.6
C5—C6—C1120.91 (9)C15—C16—H16119.6
C5—C6—H6119.5O3—C17—H17A109.5
C1—C6—H6119.5O3—C17—H17B109.5
C8—C7—C1129.40 (9)H17A—C17—H17B109.5
C8—C7—H7115.3O3—C17—H17C109.5
C1—C7—H7115.3H17A—C17—H17C109.5
C7—C8—C11120.60 (9)H17B—C17—H17C109.5
C7—C8—C19122.58 (9)O4—C18—H18A109.5
C11—C8—C19116.81 (9)O4—C18—H18B109.5
O1—C9—H9A109.5H18A—C18—H18B109.5
O1—C9—H9B109.5O4—C18—H18C109.5
H9A—C9—H9B109.5H18A—C18—H18C109.5
O1—C9—H9C109.5H18B—C18—H18C109.5
H9A—C9—H9C109.5C8—C19—Cl1111.00 (7)
H9B—C9—H9C109.5C8—C19—H19A109.4
O2—C10—H10A109.5Cl1—C19—H19A109.4
O2—C10—H10B109.5C8—C19—H19B109.4
H10A—C10—H10B109.5Cl1—C19—H19B109.4
O2—C10—H10C109.5H19A—C19—H19B108.0
C6—C1—C2—C33.52 (14)C19—C8—C11—C1640.25 (14)
C7—C1—C2—C3177.57 (9)C7—C8—C11—C1241.63 (14)
C9—O1—C3—C24.98 (15)C19—C8—C11—C12139.31 (10)
C9—O1—C3—C4174.42 (9)C16—C11—C12—C130.77 (15)
C1—C2—C3—O1178.30 (9)C8—C11—C12—C13178.80 (9)
C1—C2—C3—C41.07 (14)C17—O3—C13—C124.36 (16)
C10—O2—C4—C59.86 (16)C17—O3—C13—C14178.12 (10)
C10—O2—C4—C3169.56 (11)C11—C12—C13—O3176.96 (10)
O1—C3—C4—O21.71 (13)C11—C12—C13—C140.45 (15)
C2—C3—C4—O2177.72 (9)C18—O4—C14—C152.36 (16)
O1—C3—C4—C5178.83 (9)C18—O4—C14—C13176.73 (10)
C2—C3—C4—C51.74 (14)O3—C13—C14—O40.86 (13)
O2—C4—C5—C6177.37 (10)C12—C13—C14—O4178.48 (9)
C3—C4—C5—C62.03 (15)O3—C13—C14—C15178.29 (9)
C4—C5—C6—C10.48 (16)C12—C13—C14—C150.67 (15)
C2—C1—C6—C53.23 (15)O4—C14—C15—C16177.60 (10)
C7—C1—C6—C5177.80 (9)C13—C14—C15—C161.45 (15)
C6—C1—C7—C8148.25 (11)C12—C11—C16—C150.01 (15)
C2—C1—C7—C832.84 (16)C8—C11—C16—C15179.57 (10)
C1—C7—C8—C11176.75 (9)C14—C15—C16—C111.13 (16)
C1—C7—C8—C194.24 (17)C7—C8—C19—Cl199.79 (10)
C7—C8—C11—C16138.81 (11)C11—C8—C19—Cl181.17 (10)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C2—H2···Cl10.952.733.5800 (10)150
C12—H12···O1i0.952.573.5130 (13)170
C17—H17B···Cl1ii0.982.823.7947 (12)173
C17—H17C···O2i0.982.593.5640 (16)174
Symmetry codes: (i) x+1, y+1, z; (ii) x, y+1, z.

Experimental details

Crystal data
Chemical formulaC19H21ClO4
Mr348.81
Crystal system, space groupTriclinic, P1
Temperature (K)173
a, b, c (Å)9.2561 (1), 10.0669 (2), 11.5351 (2)
α, β, γ (°)104.620 (1), 108.441 (1), 109.692 (1)
V3)879.06 (3)
Z2
Radiation typeMo Kα
µ (mm1)0.24
Crystal size (mm)0.52 × 0.40 × 0.18
Data collection
DiffractometerSiemens SMART CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2002)
Tmin, Tmax0.887, 0.959
No. of measured, independent and
observed [I > 2σ(I)] reflections
14932, 5768, 4859
Rint0.022
(sin θ/λ)max1)0.736
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.038, 0.113, 1.02
No. of reflections5768
No. of parameters242
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.43, 0.38

Computer programs: SMART (Siemens, 1995), SAINT (Siemens, 1995), SAINT and SADABS (Sheldrick, 2002), SHELXTL (Bruker, 1997), SHELXTL, DIAMOND (Brandenburg, 2000).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C2—H2···Cl10.952.733.5800 (10)150
C12—H12···O1i0.952.573.5130 (13)170
C17—H17B···Cl1ii0.982.823.7947 (12)173
C17—H17C···O2i0.982.593.5640 (16)174
Symmetry codes: (i) x+1, y+1, z; (ii) x, y+1, z.
 

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