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Acta Cryst. (2009). E65, o763    [ doi:10.1107/S1600536809008460 ]

Ethyl 2-(3-ethylsulfinyl-5-methyl-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 ethyl 2-(3-ethylsulfanyl-5-methyl-1-benzofuran-2-yl)acetate with 3-chloroperoxybenzoic acid. The crystal structure is stabilized by aromatic [pi]-[pi] interactions between the benzene rings of neighbouring molecules [centroid-centroid distance = 3.655 (3) Å] and by three intermolecular C-H...O non-classical hydrogen bonds.

Comment top

As a part of our continuing studies on the synthesis and structure of alkyl 2-(5-methyl-3-methylsulfinyl-1-benzofuran-2-yl)acetate analogues, we have recently described the crystal structure of methyl 2-(5-methyl-3-methylsulfinyl-1-benzofuran-2-yl)acetate (Choi et al., 2008a) and isopropyl 2-(5-methyl-3-methylsulfinyl-1-benzofuran-2-yl)acetate (Choi et al., 2008b). Here we report the crystal structure of the title compound, ethyl 2-(3-ethylsulfinyl-5-methyl-1-benzofuran-2-yl)acetate (Fig. 1).

The benzofuran unit is essentially planar, with a mean deviation of 0.009 (2) Å from the least-squares plane defined by the nine constituent atoms. The molecular packing (Fig. 2) is stabilized by aromatic π-π interactions between the benzene rings of the adjacent molecules, with a Cg···Cgi distance of 3.655 (3) Å (Cg is the centroid of the C2-C7 benzene ring; symmetry codes as in Fig. 2). The crystal packing is further stabilized by intermolecular C–H···O nonclassical hydrogen bonds; one between a benzene-H atom and the O atom of the C═O unit, a second between a benzene-H atom and the O atom of the ethoxy group, a third between an H atom of the methylene group bonded to carboxylate C atom and the S═O unit, respectively (Table 1 and Fig. 2; symmetry codes as in Fig. 2).

Related literature top

For the crystal structures of similar alkyl 2-(5-methyl-3-methylsulfinyl-1-benzofuran-2-yl)acetate derivatives, see: Choi et al. (2008a,b).

Experimental top

The 77% 3-chloroperoxybenzoic acid (247 mg, 1.1 mmol) was added in small portions to a stirred solution of ethyl 2-(3-ethylsulfanyl-5-methyl-1-benzofuran-2-yl)acetate (278 mg, 1.0 mmol) in dichloromethane (30 ml) at 273 K. After being stirred for 3 h at room temperature, the mixture was washed with saturated sodium bicarbonate solution 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, 1:2 v/v) to afford the title compound as a colourless solid [yield 80%, m.p. 381-382 K; Rf = 0.51 (hexane-ethyl acetate, 1:2 v/v)]. Single crystals suitable for X-ray diffraction were prepared by evaporation of a solution of the title compound in acetone at room temperature. Spectroscopic analysis: 1H NMR (CDCl3, 400 MHz) δ 1.27 (t, J = 6.96 Hz, 3H), 1.32 (t, J = 7.32 Hz, 3H), 2.45 (s, 3H), 3.31 (q, J = 7.32 Hz, 2H), 4.04 (s, 2H), 4.20 (q, J = 7.32 Hz, 2H), 7.17 (dd, J = 8.44 Hz and 1.48 Hz, 1H), 7.39 (d, J = 8.44 Hz, 1H), 7.66 (s, 1H); EI–MS 294 [M+].

Refinement top

All H atoms were geometrically positioned and refined using a riding model, with C–H = 0.93 Å for the aryl, 0.97 Å for the methylene, and 0.96 Å for the methyl H atoms. The Uiso(H) = 1.2Ueq(C) for the aryl and methylene H atoms, and 1.5Ueq(C) for 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 with the atom numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are presented as a small spheres of arbitrary radius.
[Figure 2] Fig. 2. π-π and C–H···O interactions (dotted lines) in the title crystal structure. Cg denotes ring centroid. [Symmetry codes: (i) -x, -y+1, -z+1; (ii) -x+1, -y+1, -z+1; (iii) -x+1, -y+1, -z+2; (iv) x+1, y, z].
Ethyl 2-(3-ethylsulfinyl-5-methyl-1-benzofuran-2-yl)acetate top
Crystal data top
C15H18O4SF(000) = 624
Mr = 294.36Dx = 1.352 Mg m−3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 7772 reflections
a = 7.9651 (5) Åθ = 2.3–28.2°
b = 17.397 (1) ŵ = 0.23 mm−1
c = 10.6902 (7) ÅT = 293 K
β = 102.431 (1)°Block, colourless
V = 1446.60 (16) Å30.40 × 0.35 × 0.30 mm
Z = 4
Data collection top
Bruker SMART CCD
diffractometer		2949 reflections with I > 2σ(I)
Radiation source: Fine-focus sealed tubeRint = 0.037
graphiteθmax = 27.0°, θmin = 2.3°
Detector resolution: 10.0 pixels mm-1h = −10→10
φ and ω scansk = −22→22
12350 measured reflectionsl = −13→13
3148 independent reflections
Refinement top
Refinement on F2Primary atom site location: Direct
Least-squares matrix: FullSecondary atom site location: Difmap
R[F2 > 2σ(F2)] = 0.052Hydrogen site location: Difmap
wR(F2) = 0.114H-atom parameters constrained
S = 1.27 w = 1/[σ2(Fo2) + (0.0313P)2 + 1.0305P]
where P = (Fo2 + 2Fc2)/3
3148 reflections(Δ/σ)max < 0.001
184 parametersΔρmax = 0.28 e Å−3
0 restraintsΔρmin = −0.33 e Å−3
Crystal data top
C15H18O4SV = 1446.60 (16) Å3
Mr = 294.36Z = 4
Monoclinic, P21/cMo Kα radiation
a = 7.9651 (5) ŵ = 0.23 mm−1
b = 17.397 (1) ÅT = 293 K
c = 10.6902 (7) Å0.40 × 0.35 × 0.30 mm
β = 102.431 (1)°
Data collection top
Bruker SMART CCD
diffractometer		2949 reflections with I > 2σ(I)
12350 measured reflectionsRint = 0.037
3148 independent reflectionsθmax = 27.0°
Refinement top
R[F2 > 2σ(F2)] = 0.052H-atom parameters constrained
wR(F2) = 0.114Δρmax = 0.28 e Å−3
S = 1.27Δρmin = −0.33 e Å−3
3148 reflectionsAbsolute structure: ?
184 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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
S0.28613 (7)0.56219 (3)0.92537 (5)0.02864 (15)
O10.34278 (18)0.48031 (8)0.59291 (13)0.0264 (3)
O20.69183 (19)0.68219 (9)0.71529 (15)0.0346 (4)
O30.4106 (2)0.68573 (9)0.71809 (18)0.0420 (4)
O40.2363 (2)0.50522 (10)1.01572 (15)0.0407 (4)
C10.2712 (3)0.51603 (11)0.77684 (19)0.0251 (4)
C20.1341 (3)0.46731 (11)0.70835 (19)0.0243 (4)
C3−0.0237 (3)0.44088 (11)0.72840 (19)0.0267 (4)
H3−0.06060.45390.80250.032*
C4−0.1244 (3)0.39479 (11)0.6356 (2)0.0284 (4)
C5−0.0667 (3)0.37595 (12)0.5239 (2)0.0303 (5)
H5−0.13570.34530.46230.036*
C60.0892 (3)0.40148 (12)0.5024 (2)0.0293 (4)
H60.12660.38860.42850.035*
C70.1861 (2)0.44711 (11)0.59661 (19)0.0245 (4)
C80.3903 (3)0.52184 (11)0.70459 (19)0.0253 (4)
C90.5568 (3)0.56329 (12)0.7224 (2)0.0284 (4)
H9A0.61540.54700.65630.034*
H9B0.62800.54870.80450.034*
C100.5396 (3)0.64999 (12)0.71761 (19)0.0278 (4)
C110.6973 (3)0.76628 (13)0.7098 (2)0.0398 (6)
H11A0.81370.78380.74420.048*
H11B0.62350.78770.76230.048*
C120.6400 (4)0.79423 (16)0.5758 (3)0.0537 (7)
H12A0.70590.76930.52220.080*
H12B0.65670.84880.57340.080*
H12C0.52030.78260.54540.080*
C13−0.2954 (3)0.36439 (14)0.6536 (2)0.0385 (5)
H13A−0.28980.30940.66170.058*
H13B−0.38390.37820.58100.058*
H13C−0.32130.38630.72980.058*
C140.1037 (3)0.62590 (13)0.8750 (2)0.0352 (5)
H14A0.12470.65970.80780.042*
H14B0.00160.59580.84060.042*
C150.0745 (4)0.67308 (15)0.9860 (2)0.0464 (6)
H15A0.03340.64051.04550.070*
H15B−0.00930.71220.95550.070*
H15C0.18060.69671.02810.070*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
S0.0286 (3)0.0315 (3)0.0249 (3)0.0021 (2)0.00368 (19)−0.0026 (2)
O10.0259 (7)0.0274 (7)0.0267 (7)0.0001 (6)0.0075 (6)−0.0001 (6)
O20.0277 (8)0.0286 (8)0.0471 (9)−0.0027 (6)0.0068 (7)0.0024 (7)
O30.0333 (9)0.0303 (8)0.0651 (12)0.0018 (7)0.0169 (8)−0.0043 (8)
O40.0523 (10)0.0428 (9)0.0289 (8)0.0086 (8)0.0132 (7)0.0077 (7)
C10.0267 (10)0.0232 (10)0.0251 (10)0.0009 (8)0.0047 (8)0.0020 (8)
C20.0265 (10)0.0199 (9)0.0255 (10)0.0029 (8)0.0038 (8)0.0044 (7)
C30.0286 (10)0.0245 (10)0.0281 (10)0.0022 (8)0.0084 (8)0.0053 (8)
C40.0262 (10)0.0218 (10)0.0358 (11)0.0017 (8)0.0037 (8)0.0066 (8)
C50.0316 (11)0.0225 (10)0.0331 (11)0.0012 (8)−0.0012 (8)0.0003 (8)
C60.0347 (11)0.0249 (10)0.0277 (11)0.0034 (9)0.0056 (8)−0.0003 (8)
C70.0230 (10)0.0211 (9)0.0294 (10)0.0025 (8)0.0055 (8)0.0034 (8)
C80.0249 (10)0.0228 (9)0.0273 (10)0.0033 (8)0.0035 (8)0.0030 (8)
C90.0244 (10)0.0270 (10)0.0340 (11)0.0008 (8)0.0072 (8)0.0018 (8)
C100.0270 (10)0.0297 (11)0.0266 (10)−0.0019 (8)0.0055 (8)−0.0016 (8)
C110.0368 (13)0.0275 (11)0.0533 (15)−0.0086 (10)0.0056 (11)−0.0040 (10)
C120.0513 (16)0.0412 (14)0.0632 (18)−0.0083 (12)0.0006 (13)0.0123 (13)
C130.0309 (12)0.0327 (12)0.0513 (14)−0.0050 (9)0.0078 (10)0.0045 (10)
C140.0357 (12)0.0345 (12)0.0353 (12)0.0064 (10)0.0077 (9)0.0016 (9)
C150.0588 (17)0.0400 (14)0.0425 (14)0.0167 (12)0.0150 (12)0.0009 (11)
Geometric parameters (Å, °) top
S—O41.4960 (17)C8—C91.485 (3)
S—C11.760 (2)C9—C101.514 (3)
S—C141.815 (2)C9—H9A0.9700
O1—C81.377 (2)C9—H9B0.9700
O1—C71.384 (2)C11—C121.488 (4)
O2—C101.341 (2)C11—H11A0.9700
O2—C111.465 (3)C11—H11B0.9700
O3—C101.202 (3)C12—H12A0.9600
C1—C81.350 (3)C12—H12B0.9600
C1—C21.450 (3)C12—H12C0.9600
C2—C71.391 (3)C13—H13A0.9600
C2—C31.398 (3)C13—H13B0.9600
C3—C41.388 (3)C13—H13C0.9600
C3—H30.9300C14—C151.502 (3)
C4—C51.408 (3)C14—H14A0.9700
C4—C131.512 (3)C14—H14B0.9700
C5—C61.383 (3)C15—H15A0.9600
C5—H50.9300C15—H15B0.9600
C6—C71.380 (3)C15—H15C0.9600
C6—H60.9300
O4—S—C1107.72 (10)H9A—C9—H9B107.6
O4—S—C14106.81 (10)O3—C10—O2124.1 (2)
C1—S—C1496.70 (10)O3—C10—C9125.91 (19)
C8—O1—C7105.99 (15)O2—C10—C9109.95 (17)
C10—O2—C11116.92 (17)O2—C11—C12111.1 (2)
C8—C1—C2107.49 (18)O2—C11—H11A109.4
C8—C1—S124.25 (16)C12—C11—H11A109.4
C2—C1—S128.26 (15)O2—C11—H11B109.4
C7—C2—C3119.49 (19)C12—C11—H11B109.4
C7—C2—C1104.49 (17)H11A—C11—H11B108.0
C3—C2—C1136.00 (19)C11—C12—H12A109.5
C4—C3—C2118.71 (19)C11—C12—H12B109.5
C4—C3—H3120.6H12A—C12—H12B109.5
C2—C3—H3120.6C11—C12—H12C109.5
C3—C4—C5119.81 (19)H12A—C12—H12C109.5
C3—C4—C13120.5 (2)H12B—C12—H12C109.5
C5—C4—C13119.7 (2)C4—C13—H13A109.5
C6—C5—C4122.3 (2)C4—C13—H13B109.5
C6—C5—H5118.8H13A—C13—H13B109.5
C4—C5—H5118.8C4—C13—H13C109.5
C7—C6—C5116.40 (19)H13A—C13—H13C109.5
C7—C6—H6121.8H13B—C13—H13C109.5
C5—C6—H6121.8C15—C14—S110.46 (17)
C6—C7—O1125.83 (18)C15—C14—H14A109.6
C6—C7—C2123.28 (19)S—C14—H14A109.6
O1—C7—C2110.86 (17)C15—C14—H14B109.6
C1—C8—O1111.17 (17)S—C14—H14B109.6
C1—C8—C9132.92 (19)H14A—C14—H14B108.1
O1—C8—C9115.91 (17)C14—C15—H15A109.5
C8—C9—C10114.04 (17)C14—C15—H15B109.5
C8—C9—H9A108.7H15A—C15—H15B109.5
C10—C9—H9A108.7C14—C15—H15C109.5
C8—C9—H9B108.7H15A—C15—H15C109.5
C10—C9—H9B108.7H15B—C15—H15C109.5
O4—S—C1—C8−135.83 (18)C3—C2—C7—C6−0.1 (3)
C14—S—C1—C8114.09 (19)C1—C2—C7—C6−178.86 (18)
O4—S—C1—C245.4 (2)C3—C2—C7—O1178.44 (17)
C14—S—C1—C2−64.7 (2)C1—C2—C7—O1−0.3 (2)
C8—C1—C2—C70.3 (2)C2—C1—C8—O1−0.2 (2)
S—C1—C2—C7179.27 (15)S—C1—C8—O1−179.20 (13)
C8—C1—C2—C3−178.1 (2)C2—C1—C8—C9179.7 (2)
S—C1—C2—C30.8 (3)S—C1—C8—C90.7 (3)
C7—C2—C3—C40.1 (3)C7—O1—C8—C10.0 (2)
C1—C2—C3—C4178.4 (2)C7—O1—C8—C9−179.93 (16)
C2—C3—C4—C5−0.3 (3)C1—C8—C9—C10−67.8 (3)
C2—C3—C4—C13179.55 (18)O1—C8—C9—C10112.1 (2)
C3—C4—C5—C60.3 (3)C11—O2—C10—O3−1.6 (3)
C13—C4—C5—C6−179.5 (2)C11—O2—C10—C9179.64 (18)
C4—C5—C6—C7−0.3 (3)C8—C9—C10—O310.4 (3)
C5—C6—C7—O1−178.14 (18)C8—C9—C10—O2−170.85 (17)
C5—C6—C7—C20.2 (3)C10—O2—C11—C12−83.1 (3)
C8—O1—C7—C6178.71 (19)O4—S—C14—C1566.5 (2)
C8—O1—C7—C20.2 (2)C1—S—C14—C15177.38 (18)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C5—H5···O3i0.932.643.507 (3)155
C6—H6···O2ii0.932.633.511 (3)158
C9—H9B···O4iii0.972.203.161 (3)169
Symmetry codes: (i) −x, −y+1, −z+1; (ii) −x+1, −y+1, −z+1; (iii) −x+1, −y+1, −z+2.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C5—H5···O3i0.932.643.507 (3)155
C6—H6···O2ii0.932.633.511 (3)158
C9—H9B···O4iii0.972.203.161 (3)169
Symmetry codes: (i) −x, −y+1, −z+1; (ii) −x+1, −y+1, −z+1; (iii) −x+1, −y+1, −z+2.
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. (2008a). Acta Cryst. E64, o1711.

Choi, H. D., Seo, P. J., Son, B. W. & Lee, U. (2008b). Acta Cryst. E64, o2079.

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

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