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Acta Crystallogr Sect E Struct Rep Online. 2008 June 1; 64(Pt 6): o1143.
Published online 2008 May 24. doi:  10.1107/S1600536808015031
PMCID: PMC2961357

2,4,6,7-Tetra­methyl-3-phenyl­sulfinyl-1-benzofuran

Abstract

In the title compound, C18H18O2S, the O atom and the phenyl group of the phenyl­sulfinyl substituent lie on opposite sides of the planar benzofuran fragment. The phenyl ring is nearly perpendicular to the benzofuran system [88.56 (7)°] and is tilted slightly towards it. Molecules form pseudo-helices along the a axis. The crystal structure is stabilized by a C—H(...)π inter­action between a methyl H atom and the phenyl ring of the phenyl­sulfinyl substituent, and by intra- and inter­molecular C—H(...)O inter­actions.

Related literature

For details of the pharmacological properties of benzofuran compounds, see: Howlett et al. (1999 [triangle]); Ward (1997 [triangle]). For the structures of other benzofuran derivatives, see: Choi et al. (2007 [triangle], 2008 [triangle]).

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Object name is e-64-o1143-scheme1.jpg

Experimental

Crystal data

  • C18H18O2S
  • M r = 298.38
  • Orthorhombic, An external file that holds a picture, illustration, etc.
Object name is e-64-o1143-efi11.jpg
  • a = 12.0402 (6) Å
  • b = 19.673 (1) Å
  • c = 6.4399 (3) Å
  • V = 1525.40 (13) Å3
  • Z = 4
  • Mo Kα radiation
  • μ = 0.21 mm−1
  • T = 173 (2) K
  • 0.40 × 0.40 × 0.30 mm

Data collection

  • Bruker SMART CCD diffractometer
  • Absorption correction: none
  • 9082 measured reflections
  • 2486 independent reflections
  • 2339 reflections with I > 2σ(I)
  • R int = 0.102

Refinement

  • R[F 2 > 2σ(F 2)] = 0.051
  • wR(F 2) = 0.138
  • S = 1.08
  • 2486 reflections
  • 194 parameters
  • 1 restraint
  • H-atom parameters constrained
  • Δρmax = 0.51 e Å−3
  • Δρmin = −0.43 e Å−3

Data collection: SMART (Bruker, 2001 [triangle]); cell refinement: SAINT (Bruker, 2001 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: ORTEP-3 (Farrugia, 1997 [triangle]) and DIAMOND (Brandenburg, 1998 [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/S1600536808015031/fl2196sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808015031/fl2196Isup2.hkl

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

supplementary crystallographic information

Comment

Benzofuran ring systems have attracted considerable interest because of their various pharmacological properties (Howlett et al., 1999; Ward, 1997). This work is related to earlier communications on the synthesis and structure of similar benzofuran analogues (Choi et al., 2007, 2008)

In the title commmpound, the benzofuran unit is essentially planar, with a mean deviation of 0.008 Å from the least-squares plane defined by the nine constituent atoms (Fig. 1). The phenyl ring (C9-C14) is almost perpendicular to the plane of the benzofuran system [88.56 (7)°] and is tilted slightly towards it.

The title commpound crystallized in the non-centrosymmetric space group Pna21 in spite of having no asymmetric carbon atoms. The space group was caused by a right handed pseudo-helix along the a axis. In addition, the molecular packing (Fig. 2) is stabilized by a C—H···π interaction between a methyl H atom and the phenyl ring of the phenylsulfinyl substituent, with a C17—17A···Cgi separation of 3.565 (5) Å (Fig. 2 and Table1; Cg is the centroid of C9-C14 phenyl ring). The molecular packing is further stabilized by intra- and intermolecular C—H···O interactions (Fig. 2 and Table 1: symmetry code as in Fig. 2).

Experimental

3-Chloroperoxybenzoic acid (77%, 190 mg, 0.85 mmol) was added in small portions to a stirred solution of 2,4,6,7-tetramethyl-3-phenylsulfanyl-1-benzofuran (226 mg, 0.8 mmol) in dichloromethane (20 ml) at 273 K. After being stirred at room temperature for 2h, the mixture was washed with a saturated soution of sodium bicarbonate and the organic layer was separated, dried over magnesium sulfate, filtered and concentrated in vacuum. The residue was purified by column chromatography (hexane-ethyl acetate, 2:1 v/v) to afford the title compound as a colorless solid [yield 80%, m.p. 407-408 K; Rf = 0.54 (hexane-ethyl acetate, 2:1 v/v)]. Single crystals suitable for X-ray diffraction were prepared by slow evaporation from acetone at room temperature. Spectroscopic analysis: 1H NMR (CDCl3, 400 MHz) δ 2.13 (s, 3H), 2.29 (s, 3H), 2.37 (s, 3H), 2.71 (s, 3H), 6.77 (s, 1H), 7.39-7.45 (m, 3H), 7.48-7.51 (m, 2H); EI-MS 298 [M+].

Refinement

All H atoms were positioned geometrically and refined using a riding model, with C—H = 0.95 Å for aromatic H atoms and 0.98 Å for methyl H atoms, respectively, and with Uiso(H) = 1.2Ueq(C) for aromatic H atoms and 1.5Ueq(C) for methyl H atoms. Friedel pairs were merged at final refinement.

Figures

Fig. 1.
The molecular structure of the title compound, showing displacement ellipsoids drawn at the 50% probability level.
Fig. 2.
View of the structure projected on the ab plane. C—H···π and C—H···O interactions are shown as dotted lines. Cg denotes the ring centroid. [Symmetry code: (i)x-1/2, -y+3/2, z; (ii) ...

Crystal data

C18H18O2SF000 = 632
Mr = 298.38Dx = 1.299 Mg m3
Orthorhombic, Pna21Mo Kα radiation λ = 0.71073 Å
Hall symbol: p_2c_-2nCell parameters from 5414 reflections
a = 12.0402 (6) Åθ = 2.7–28.2º
b = 19.673 (1) ŵ = 0.21 mm1
c = 6.4399 (3) ÅT = 173 (2) K
V = 1525.40 (13) Å3Block, colorless
Z = 40.40 × 0.40 × 0.30 mm

Data collection

Bruker SMART CCD diffractometer2486 independent reflections
Radiation source: fine-focus sealed tube2339 reflections with I > 2σ(I)
Monochromator: graphiteRint = 0.102
Detector resolution: 10.0 pixels mm-1θmax = 27.0º
T = 173(2) Kθmin = 2.7º
[var phi] and ω scansh = −14→15
Absorption correction: nonek = −25→24
9082 measured reflectionsl = −8→4

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.051H-atom parameters constrained
wR(F2) = 0.138  w = 1/[σ2(Fo2) + (0.0864P)2 + 0.5202P] where P = (Fo2 + 2Fc2)/3
S = 1.09(Δ/σ)max < 0.001
2486 reflectionsΔρmax = 0.51 e Å3
194 parametersΔρmin = −0.43 e Å3
1 restraintExtinction correction: none
Primary atom site location: structure-invariant direct methods

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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)

xyzUiso*/Ueq
S0.60317 (5)0.74039 (3)0.74685 (15)0.0220 (2)
O10.33116 (17)0.63540 (10)0.8280 (4)0.0229 (5)
O20.71121 (16)0.70681 (11)0.6963 (4)0.0308 (6)
C10.4924 (2)0.68198 (13)0.7252 (5)0.0200 (6)
C20.4634 (2)0.63018 (13)0.5731 (5)0.0199 (6)
C30.5073 (3)0.60387 (14)0.3879 (6)0.0237 (6)
C40.4461 (3)0.55262 (15)0.2916 (5)0.0274 (7)
H40.47440.53360.16680.033*
C50.3448 (3)0.52741 (14)0.3689 (6)0.0277 (7)
C60.3011 (2)0.55259 (14)0.5539 (6)0.0245 (7)
C70.3638 (2)0.60360 (14)0.6471 (5)0.0207 (6)
C80.4118 (2)0.68331 (14)0.8720 (5)0.0205 (6)
C90.5685 (2)0.79514 (14)0.5322 (5)0.0204 (6)
C100.4647 (3)0.82691 (15)0.5279 (6)0.0274 (7)
H100.41010.81710.63000.033*
C110.4437 (3)0.87313 (16)0.3706 (7)0.0339 (8)
H110.37340.89500.36400.041*
C120.5237 (3)0.88799 (16)0.2224 (7)0.0344 (8)
H120.50810.92020.11630.041*
C130.6266 (3)0.85595 (15)0.2287 (7)0.0290 (7)
H130.68110.86580.12640.035*
C140.6494 (2)0.80925 (14)0.3858 (6)0.0235 (7)
H140.71960.78740.39230.028*
C150.6131 (3)0.62939 (17)0.2903 (6)0.0281 (8)
H15A0.64360.59430.19860.042*
H15B0.66720.64000.39940.042*
H15C0.59750.67050.20950.042*
C160.2833 (3)0.47364 (15)0.2454 (9)0.0399 (9)
H16A0.28980.42970.31600.060*
H16B0.31560.47030.10610.060*
H16C0.20470.48620.23440.060*
C170.1937 (3)0.52894 (17)0.6488 (7)0.0337 (8)
H17A0.13140.55210.58120.051*
H17B0.19350.53960.79750.051*
H17C0.18620.47970.62960.051*
C180.3902 (3)0.72565 (17)1.0569 (6)0.0270 (7)
H18A0.45560.75361.08680.041*
H18B0.37430.69631.17610.041*
H18C0.32620.75521.03040.041*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
S0.0194 (3)0.0245 (3)0.0222 (4)−0.0027 (2)−0.0002 (3)−0.0011 (4)
O10.0215 (10)0.0254 (10)0.0219 (12)−0.0032 (8)0.0032 (9)0.0003 (9)
O20.0200 (10)0.0354 (11)0.0369 (16)0.0011 (8)−0.0010 (10)0.0046 (10)
C10.0186 (12)0.0206 (12)0.0208 (17)−0.0016 (9)−0.0004 (12)0.0020 (13)
C20.0207 (14)0.0170 (12)0.0219 (16)0.0013 (10)−0.0010 (13)0.0037 (12)
C30.0248 (14)0.0217 (14)0.0245 (17)0.0062 (10)0.0002 (13)0.0007 (13)
C40.0332 (16)0.0252 (14)0.0239 (19)0.0066 (11)−0.0020 (14)−0.0058 (12)
C50.0322 (17)0.0164 (12)0.034 (2)0.0029 (11)−0.0089 (15)−0.0041 (14)
C60.0234 (14)0.0177 (12)0.0323 (19)0.0013 (10)−0.0036 (14)0.0047 (13)
C70.0201 (12)0.0185 (12)0.0234 (17)0.0022 (10)0.0002 (13)0.0037 (12)
C80.0194 (13)0.0212 (13)0.0210 (16)−0.0017 (10)0.0018 (13)0.0036 (12)
C90.0205 (13)0.0170 (13)0.0237 (16)0.0009 (10)−0.0002 (12)−0.0011 (12)
C100.0232 (15)0.0250 (14)0.0340 (19)−0.0003 (11)0.0061 (14)−0.0015 (13)
C110.0251 (16)0.0282 (16)0.048 (2)0.0039 (11)0.0034 (16)0.0082 (16)
C120.0428 (18)0.0261 (14)0.034 (2)−0.0007 (12)0.0011 (17)0.0064 (16)
C130.0305 (15)0.0271 (14)0.029 (2)−0.0045 (11)0.0062 (17)0.0021 (16)
C140.0204 (14)0.0217 (12)0.0282 (18)0.0002 (10)0.0054 (13)−0.0048 (13)
C150.0266 (15)0.0333 (15)0.025 (2)0.0041 (11)0.0058 (14)−0.0023 (13)
C160.0422 (18)0.0277 (15)0.050 (2)−0.0004 (12)−0.007 (2)−0.012 (2)
C170.0294 (16)0.0307 (16)0.041 (2)−0.0080 (12)−0.0016 (16)0.0059 (16)
C180.0251 (16)0.0323 (15)0.0236 (18)−0.0001 (12)0.0020 (14)−0.0031 (14)

Geometric parameters (Å, °)

S—O21.495 (2)C10—H100.9500
S—C11.766 (3)C11—C121.387 (5)
S—C91.801 (3)C11—H110.9500
O1—C71.379 (4)C12—C131.391 (5)
O1—C81.383 (3)C12—H120.9500
C1—C81.355 (4)C13—C141.394 (5)
C1—C21.456 (4)C13—H130.9500
C2—C71.393 (4)C14—H140.9500
C2—C31.403 (5)C15—H15A0.9800
C3—C41.394 (4)C15—H15B0.9800
C3—C151.507 (4)C15—H15C0.9800
C4—C51.408 (5)C16—H16A0.9800
C4—H40.9500C16—H16B0.9800
C5—C61.393 (5)C16—H16C0.9800
C5—C161.516 (5)C17—H17A0.9800
C6—C71.392 (4)C17—H17B0.9800
C6—C171.504 (5)C17—H17C0.9800
C8—C181.476 (5)C18—H18A0.9800
C9—C141.383 (5)C18—H18B0.9800
C9—C101.398 (4)C18—H18C0.9800
C10—C111.385 (5)
O2—S—C1110.63 (13)C10—C11—H11119.5
O2—S—C9107.37 (15)C12—C11—H11119.5
C1—S—C998.84 (14)C11—C12—C13120.2 (3)
C7—O1—C8106.4 (2)C11—C12—H12119.9
C8—C1—C2108.1 (2)C13—C12—H12119.9
C8—C1—S118.2 (2)C12—C13—C14119.7 (3)
C2—C1—S133.6 (2)C12—C13—H13120.2
C7—C2—C3118.5 (3)C14—C13—H13120.2
C7—C2—C1103.8 (3)C9—C14—C13119.2 (3)
C3—C2—C1137.7 (3)C9—C14—H14120.4
C4—C3—C2116.5 (3)C13—C14—H14120.4
C4—C3—C15120.1 (3)C3—C15—H15A109.5
C2—C3—C15123.4 (3)C3—C15—H15B109.5
C3—C4—C5123.7 (3)H15A—C15—H15B109.5
C3—C4—H4118.1C3—C15—H15C109.5
C5—C4—H4118.1H15A—C15—H15C109.5
C6—C5—C4120.3 (3)H15B—C15—H15C109.5
C6—C5—C16120.8 (3)C5—C16—H16A109.5
C4—C5—C16118.9 (3)C5—C16—H16B109.5
C7—C6—C5114.9 (3)H16A—C16—H16B109.5
C7—C6—C17120.9 (3)C5—C16—H16C109.5
C5—C6—C17124.2 (3)H16A—C16—H16C109.5
O1—C7—C6122.5 (3)H16B—C16—H16C109.5
O1—C7—C2111.3 (3)C6—C17—H17A109.5
C6—C7—C2126.2 (3)C6—C17—H17B109.5
C1—C8—O1110.3 (3)H17A—C17—H17B109.5
C1—C8—C18134.4 (3)C6—C17—H17C109.5
O1—C8—C18115.2 (3)H17A—C17—H17C109.5
C14—C9—C10121.7 (3)H17B—C17—H17C109.5
C14—C9—S118.7 (2)C8—C18—H18A109.5
C10—C9—S119.3 (3)C8—C18—H18B109.5
C11—C10—C9118.1 (3)H18A—C18—H18B109.5
C11—C10—H10120.9C8—C18—H18C109.5
C9—C10—H10120.9H18A—C18—H18C109.5
C10—C11—C12121.0 (3)H18B—C18—H18C109.5
O2—S—C1—C8138.4 (2)C5—C6—C7—C2−0.3 (4)
C9—S—C1—C8−109.2 (3)C17—C6—C7—C2−179.2 (3)
O2—S—C1—C2−43.7 (3)C3—C2—C7—O1−179.1 (2)
C9—S—C1—C268.7 (3)C1—C2—C7—O10.4 (3)
C8—C1—C2—C7−0.5 (3)C3—C2—C7—C6−0.4 (5)
S—C1—C2—C7−178.5 (2)C1—C2—C7—C6179.2 (3)
C8—C1—C2—C3179.0 (3)C2—C1—C8—O10.3 (3)
S—C1—C2—C30.9 (6)S—C1—C8—O1178.72 (19)
C7—C2—C3—C40.2 (4)C2—C1—C8—C18−176.4 (3)
C1—C2—C3—C4−179.2 (3)S—C1—C8—C182.0 (5)
C7—C2—C3—C15178.8 (3)C7—O1—C8—C10.0 (3)
C1—C2—C3—C15−0.6 (6)C7—O1—C8—C18177.4 (3)
C2—C3—C4—C50.6 (5)O2—S—C9—C14−13.1 (3)
C15—C3—C4—C5−178.0 (3)C1—S—C9—C14−128.1 (3)
C3—C4—C5—C6−1.4 (5)O2—S—C9—C10172.6 (2)
C3—C4—C5—C16177.4 (3)C1—S—C9—C1057.6 (3)
C4—C5—C6—C71.2 (4)C14—C9—C10—C110.5 (5)
C16—C5—C6—C7−177.6 (3)S—C9—C10—C11174.7 (3)
C4—C5—C6—C17−180.0 (3)C9—C10—C11—C12−0.6 (5)
C16—C5—C6—C171.3 (5)C10—C11—C12—C130.6 (6)
C8—O1—C7—C6−179.1 (3)C11—C12—C13—C14−0.6 (5)
C8—O1—C7—C2−0.3 (3)C10—C9—C14—C13−0.5 (5)
C5—C6—C7—O1178.3 (3)S—C9—C14—C13−174.7 (2)
C17—C6—C7—O1−0.6 (5)C12—C13—C14—C90.6 (5)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
C17—H17A···Cgi0.982.683.565 (5)151
C10—H10···O2i0.952.483.306 (4)146
C15—H15B···O20.982.383.248 (4)147

Symmetry codes: (i) x−1/2, −y+3/2, z.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: FL2196).

References

  • Brandenburg, K. (1998). DIAMOND Crystal Impact GbR, Bonn, Germany.
  • Bruker (2001). SAINT and SMART Bruker AXS Inc., Madison, Wisconsin, USA.
  • Choi, H. D., Seo, P. J., Son, B. W. & Lee, U. (2007). Acta Cryst. E63, o4042.
  • Choi, H. D., Seo, P. J., Son, B. W. & Lee, U. (2008). Acta Cryst. E64, o486. [PMC free article] [PubMed]
  • Farrugia, L. J. (1997). J. Appl. Cryst.30, 565.
  • Howlett, D. R., Perry, A. E., Godfrey, F., Swatton, J. E., Jennings, K. H., Spitzfaden, C., Wadsworth, H., Wood, S. J. & Markwell, R. E. (1999). Biochem. J.340, 283–289. [PubMed]
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Ward, R. S. (1997). Nat. Prod. Rep.14, 43–74.

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