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Acta Cryst. (2008). E64, o2079    [ doi:10.1107/S1600536808031796 ]

Isopropyl 2-(5-methyl-3-methylsulfinyl-1-benzofuran-2-yl)acetate

H. D. Choi, P. J. Seo, B. W. Son and U. Lee

Abstract top

The title compound, C15H18O4S, was prepared by the oxidation of isopropyl 2-(5-methyl-3-methylsulfanyl-1-benzofuran-2-yl)acetate with 3-chloroperoxybenzoic acid. The crystal structure is stabilized by intermolecular [pi]-[pi] interactions between the benzene rings; the centroid-centroid distance between the adjacent benzene rings (symmetry code: 1-x, 1-y, 1-z) is 3.713 (2) Å. In addition, C-H...[pi] and weak intermolecular C-H...O interactions are present in the structure.

Comment top

This work is related to our previous communications on the synthesis and structure of 2-(5-methyl-3-methylsulfinyl-1-benzofuran-2-yl)acetic acid analogues, viz. ethyl 2-(5-methyl-3-methylsulfinyl-1-benzofuran-2-yl)acetate (Choi et al., 2007) and methyl 2-(5-methyl-3-methylsulfinyl-1-benzofuran-2-yl)acetate (Choi et al., 2008). Here we report the crystal structure of the title compound, isopropyl 2-(5-methyl-3-methylsulfinyl-1-benzofuran-2-yl)acetate (Fig. 1).

The benzofuran unit is essentially planar, with a mean deviation of 0.004 (1) Å from the least-squares plane defined by the nine constituent atoms. The molecular packing (Fig. 2) is stabilized by π—π electron interactions between the benzofuran rings of the adjacent molecules. The distances between the centroids of the stacked benzene rings are 3.713 (2) Å (symmetry code: 1-x, 1-y, 1-z). The crystal packing is further stabilized by C—H···π electron interactions (Tab. 1). Additionally, intermolecular C—H···O interactions are present in the structure (Tab. 1).

Related literature top

For the crystal structures of similar 2-(5-methyl-3-methylsulfinyl-1-benzofuran-2-yl)acetic acid derivatives, see: Choi et al. (2007, 2008).

Experimental top

77% 3-chloroperoxybenzoic acid (471 mg, 2.1 mmol) was added in small portions to a stirred solution of isopropyl 2-(5-methyl-3-methylsulfanyl-1-benzofuran-2-yl)acetate (556 mg, 2.0 mmol) in dichloromethane (40 ml) at 273 K. After having been stirred for 3 h at room temperature, the mixture was washed with saturated sodium hydrogencarbonate solution and the organic layer was separated, dried over magnesium sulfate, filtered and concentrated under vacuum. The residue was purified by column chromatography (ethyl acetate) to afford the title compound as a colorless solid [yield 81%, m.p. 403–404 K; Rf = 0.74 (ethyl acetate)]. Single crystals suitable for X-ray diffraction were prepared by evaporation of a solution of the title compound in ethyl acetate at room temperature. The average crystal size was approximately 1.0 x 1.0 x 0.5 mm. The crystals are colourless and soluble in polar solvents. Spectroscopic analysis: 1H NMR (CDCl3, 400 MHz) δ 1.25 (d, J = 6.20 Hz, 6H), 2.46 (s, 3H), 3.08 (s, 3H), 3.99 (s, 2H), 5.00–5.08 (m, 1H), 7.17 (d, J = 8.44 Hz, 1H), 7.39 (d, J = 8.44 Hz, 1H), 7.74 (s, 1H); EI—MS 294 [M+].

Refinement top

All the hydrogen atoms could have been distinguished in the difference electron density maps. However, all the H atoms were positioned geometrically and refined using a riding model, with C—H = 0.93 Å for the aryl, 0.97 Å for the methylene, 0.98 Å for the methine and 0.96 Å for the methyl H atoms. Uiso(H) = 1.2Ueq(C) for the aryl, methine and methylene H atoms, and Uiso(H) = 1.5Ueq(C) for the methyl H atoms.

Computing details top

Data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 1998); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, showing the displacement ellipsoids drawn at the 30% probability level.
[Figure 2] Fig. 2. π—π, C—H···π and C—H···O interactions (dotted lines) in the title compound. Cg denotes the ring centroid. [Symmetry codes: (i) -x + 2, -y + 1, -z; (ii) x, y + 1, z; (iii) -x + 1, -y+, -z + 1; (iv) x, y - 1, z.]
Isopropyl 2-(5-methyl-3-methylsulfinyl-1-benzofuran-2-yl)acetate top
Crystal data top
C15H18O4SZ = 2
Mr = 294.35F(000) = 312
Triclinic, P1Dx = 1.327 Mg m−3
Hall symbol: -P_1Melting point = 403–404 K
a = 8.1829 (5) ÅMo Kα radiation, λ = 0.71073 Å
b = 9.7027 (6) ÅCell parameters from 4030 reflections
c = 10.6545 (7) Åθ = 2.4–28.2°
α = 73.057 (1)°µ = 0.23 mm−1
β = 77.463 (1)°T = 298 K
γ = 66.421 (1)°Block, colourless
V = 736.76 (8) Å30.40 × 0.30 × 0.30 mm
Data collection top
Bruker SMART CCD
diffractometer		2479 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.035
graphiteθmax = 26.0°, θmin = 2.7°
Detector resolution: 10.0 pixels mm-1h = −10→10
φ and ω scansk = −11→11
5802 measured reflectionsl = −13→13
2838 independent reflections
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)] = 0.036Hydrogen site location: difference Fourier map
wR(F2) = 0.105H-atom parameters constrained
S = 1.07 w = 1/[σ2(Fo2) + (0.0509P)2 + 0.2101P]
where P = (Fo2 + 2Fc2)/3
2838 reflections(Δ/σ)max < 0.001
185 parametersΔρmax = 0.22 e Å−3
0 restraintsΔρmin = −0.24 e Å−3
68 constraints
Crystal data top
C15H18O4Sγ = 66.421 (1)°
Mr = 294.35V = 736.76 (8) Å3
Triclinic, P1Z = 2
a = 8.1829 (5) ÅMo Kα radiation
b = 9.7027 (6) ŵ = 0.23 mm−1
c = 10.6545 (7) ÅT = 298 K
α = 73.057 (1)°0.40 × 0.30 × 0.30 mm
β = 77.463 (1)°
Data collection top
Bruker SMART CCD
diffractometer		2479 reflections with I > 2σ(I)
5802 measured reflectionsRint = 0.035
2838 independent reflectionsθmax = 26.0°
Refinement top
R[F2 > 2σ(F2)] = 0.036H-atom parameters constrained
wR(F2) = 0.105Δρmax = 0.22 e Å−3
S = 1.07Δρmin = −0.24 e Å−3
2838 reflectionsAbsolute structure: ?
185 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

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
S0.74200 (6)0.64759 (5)0.04151 (4)0.04706 (16)
O10.84827 (15)0.47478 (12)0.40980 (11)0.0378 (3)
O20.7528 (2)0.53592 (18)−0.03283 (14)0.0705 (4)
O30.73496 (17)0.88857 (15)0.23749 (16)0.0603 (4)
O41.00780 (15)0.88109 (12)0.25158 (12)0.0422 (3)
C10.7543 (2)0.55223 (18)0.20899 (15)0.0356 (3)
C20.6619 (2)0.45172 (16)0.29204 (15)0.0336 (3)
C30.5364 (2)0.39518 (18)0.27713 (16)0.0380 (4)
H30.49130.42330.19670.046*
C40.4806 (2)0.29641 (19)0.38454 (17)0.0405 (4)
C50.5499 (2)0.25528 (19)0.50517 (17)0.0424 (4)
H50.51090.18880.57610.051*
C60.6736 (2)0.30967 (18)0.52246 (16)0.0401 (4)
H60.71890.28180.60270.048*
C70.7260 (2)0.40767 (17)0.41396 (15)0.0343 (3)
C80.8622 (2)0.56095 (18)0.28352 (15)0.0361 (3)
C90.9868 (2)0.64659 (18)0.25585 (18)0.0405 (4)
H9A1.06070.63210.17280.049*
H9B1.06570.60290.32470.049*
C100.8915 (2)0.81825 (18)0.24831 (16)0.0384 (4)
C110.3469 (3)0.2312 (3)0.3719 (2)0.0598 (5)
H11A0.29590.28460.29020.090*
H11B0.25330.24430.44430.090*
H11C0.40660.12320.37310.090*
C120.5114 (3)0.7722 (3)0.0561 (2)0.0717 (6)
H12A0.48140.8392−0.02840.108*
H12B0.49260.83320.11820.108*
H12C0.43670.71120.08650.108*
C130.9392 (2)1.04906 (18)0.24297 (18)0.0426 (4)
H130.82391.07910.29820.051*
C140.9158 (3)1.1356 (2)0.1023 (2)0.0603 (5)
H14A0.83231.11040.07070.090*
H14B1.02941.10710.04880.090*
H14C0.87081.24460.09740.090*
C151.0762 (3)1.0762 (2)0.2963 (3)0.0692 (6)
H15A1.19071.04070.24530.104*
H15B1.08501.02060.38680.104*
H15C1.04071.18460.29100.104*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
S0.0572 (3)0.0469 (3)0.0365 (2)−0.0241 (2)−0.00906 (19)0.00182 (17)
O10.0416 (6)0.0381 (6)0.0392 (6)−0.0204 (5)−0.0113 (5)−0.0035 (5)
O20.0994 (12)0.0694 (9)0.0444 (8)−0.0262 (9)−0.0159 (8)−0.0158 (7)
O30.0408 (7)0.0449 (7)0.0966 (11)−0.0190 (6)−0.0103 (7)−0.0113 (7)
O40.0420 (6)0.0328 (6)0.0568 (7)−0.0177 (5)−0.0114 (5)−0.0075 (5)
C10.0406 (8)0.0324 (7)0.0355 (8)−0.0163 (7)−0.0064 (6)−0.0040 (6)
C20.0373 (8)0.0292 (7)0.0352 (8)−0.0128 (6)−0.0055 (6)−0.0067 (6)
C30.0411 (9)0.0370 (8)0.0415 (8)−0.0167 (7)−0.0096 (7)−0.0098 (7)
C40.0394 (9)0.0362 (8)0.0512 (10)−0.0175 (7)−0.0047 (7)−0.0124 (7)
C50.0458 (9)0.0356 (8)0.0454 (9)−0.0205 (7)−0.0016 (7)−0.0031 (7)
C60.0449 (9)0.0377 (8)0.0375 (8)−0.0165 (7)−0.0095 (7)−0.0024 (6)
C70.0357 (8)0.0304 (7)0.0394 (8)−0.0140 (6)−0.0076 (6)−0.0063 (6)
C80.0395 (8)0.0312 (7)0.0386 (8)−0.0159 (6)−0.0057 (6)−0.0040 (6)
C90.0396 (9)0.0376 (8)0.0490 (9)−0.0200 (7)−0.0070 (7)−0.0068 (7)
C100.0394 (9)0.0387 (8)0.0397 (8)−0.0206 (7)−0.0038 (7)−0.0038 (6)
C110.0605 (12)0.0615 (12)0.0731 (13)−0.0393 (10)−0.0128 (10)−0.0095 (10)
C120.0665 (14)0.0616 (13)0.0692 (14)−0.0084 (11)−0.0246 (11)0.0023 (11)
C130.0444 (9)0.0327 (8)0.0540 (10)−0.0160 (7)−0.0051 (8)−0.0119 (7)
C140.0797 (15)0.0395 (10)0.0607 (12)−0.0235 (10)−0.0124 (10)−0.0039 (8)
C150.0745 (15)0.0483 (11)0.1006 (18)−0.0231 (11)−0.0311 (13)−0.0232 (11)
Geometric parameters (Å, °) top
S—O21.4839 (15)C8—C91.490 (2)
S—C11.7583 (16)C9—C101.516 (2)
S—C121.790 (2)C9—H9A0.9700
O1—C81.3698 (18)C9—H9B0.9700
O1—C71.3830 (18)C11—H11A0.9600
O3—C101.199 (2)C11—H11B0.9600
O4—C101.3305 (19)C11—H11C0.9600
O4—C131.4774 (19)C12—H12A0.9600
C1—C81.349 (2)C12—H12B0.9600
C1—C21.450 (2)C12—H12C0.9600
C2—C71.392 (2)C13—C151.500 (3)
C2—C31.397 (2)C13—C141.500 (3)
C3—C41.386 (2)C13—H130.9800
C3—H30.9300C14—H14A0.9600
C4—C51.403 (2)C14—H14B0.9600
C4—C111.511 (2)C14—H14C0.9600
C5—C61.379 (2)C15—H15A0.9600
C5—H50.9300C15—H15B0.9600
C6—C71.376 (2)C15—H15C0.9600
C6—H60.9300
O2—S—C1108.11 (8)H9A—C9—H9B107.7
O2—S—C12106.21 (11)O3—C10—O4124.63 (15)
C1—S—C1297.74 (9)O3—C10—C9125.20 (14)
C8—O1—C7106.03 (11)O4—C10—C9110.14 (13)
C10—O4—C13117.80 (13)C4—C11—H11A109.5
C8—C1—C2107.31 (13)C4—C11—H11B109.5
C8—C1—S123.03 (12)H11A—C11—H11B109.5
C2—C1—S129.65 (12)C4—C11—H11C109.5
C7—C2—C3119.08 (14)H11A—C11—H11C109.5
C7—C2—C1104.42 (13)H11B—C11—H11C109.5
C3—C2—C1136.50 (15)S—C12—H12A109.5
C4—C3—C2118.66 (15)S—C12—H12B109.5
C4—C3—H3120.7H12A—C12—H12B109.5
C2—C3—H3120.7S—C12—H12C109.5
C3—C4—C5119.95 (15)H12A—C12—H12C109.5
C3—C4—C11120.26 (16)H12B—C12—H12C109.5
C5—C4—C11119.79 (16)O4—C13—C15105.45 (14)
C6—C5—C4122.50 (15)O4—C13—C14109.85 (14)
C6—C5—H5118.7C15—C13—C14112.29 (17)
C4—C5—H5118.7O4—C13—H13109.7
C7—C6—C5116.08 (15)C15—C13—H13109.7
C7—C6—H6122.0C14—C13—H13109.7
C5—C6—H6122.0C13—C14—H14A109.5
C6—C7—O1125.47 (14)C13—C14—H14B109.5
C6—C7—C2123.73 (14)H14A—C14—H14B109.5
O1—C7—C2110.80 (13)C13—C14—H14C109.5
C1—C8—O1111.44 (13)H14A—C14—H14C109.5
C1—C8—C9132.89 (15)H14B—C14—H14C109.5
O1—C8—C9115.66 (13)C13—C15—H15A109.5
C8—C9—C10113.54 (14)C13—C15—H15B109.5
C8—C9—H9A108.9H15A—C15—H15B109.5
C10—C9—H9A108.9C13—C15—H15C109.5
C8—C9—H9B108.9H15A—C15—H15C109.5
C10—C9—H9B108.9H15B—C15—H15C109.5
O2—S—C1—C8133.07 (16)C3—C2—C7—C60.4 (2)
C12—S—C1—C8−117.00 (17)C1—C2—C7—C6−179.35 (15)
O2—S—C1—C2−45.61 (17)C3—C2—C7—O1−179.98 (13)
C12—S—C1—C264.32 (17)C1—C2—C7—O10.30 (17)
C8—C1—C2—C70.00 (18)C2—C1—C8—O1−0.30 (19)
S—C1—C2—C7178.83 (13)S—C1—C8—O1−179.23 (11)
C8—C1—C2—C3−179.65 (18)C2—C1—C8—C9−178.84 (17)
S—C1—C2—C3−0.8 (3)S—C1—C8—C92.2 (3)
C7—C2—C3—C4−0.3 (2)C7—O1—C8—C10.48 (18)
C1—C2—C3—C4179.36 (17)C7—O1—C8—C9179.29 (13)
C2—C3—C4—C50.1 (2)C1—C8—C9—C1074.3 (2)
C2—C3—C4—C11−179.20 (16)O1—C8—C9—C10−104.20 (16)
C3—C4—C5—C60.0 (3)C13—O4—C10—O30.8 (2)
C11—C4—C5—C6179.31 (17)C13—O4—C10—C9179.02 (13)
C4—C5—C6—C70.1 (3)C8—C9—C10—O3−14.9 (2)
C5—C6—C7—O1−179.86 (15)C8—C9—C10—O4166.85 (14)
C5—C6—C7—C2−0.3 (2)C10—O4—C13—C15160.41 (17)
C8—O1—C7—C6179.16 (15)C10—O4—C13—C14−78.39 (19)
C8—O1—C7—C2−0.48 (17)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C9—H9A···O2i0.972.383.249 (2)149
C13—H13···Cg1ii0.982.913.656 (2)134
C15—H15C···Cg2ii0.962.963.837 (2)152
Symmetry codes: (i) −x+2, −y+1, −z; (ii) x, y+1, z.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C9—H9A···O2i0.972.383.249 (2)149
C13—H13···Cg1ii0.982.913.656 (2)134
C15—H15C···Cg2ii0.962.963.837 (2)152
Symmetry codes: (i) −x+2, −y+1, −z; (ii) x, y+1, z.
references
References top

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, o3839.

Choi, H. D., Seo, P. J., Son, B. W. & Lee, U. (2008). Acta Cryst. E64, o1711.

Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.