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Acta Cryst. (2009). E65, o1498    [ doi:10.1107/S1600536809020613 ]

Isoamyl 2-(5-bromo-3-methylsulfinyl-1-benzofuran-2-yl)acetate

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

Abstract top

In the title compound, C16H19BrO4S, the O atom and the methyl group of the methylsulfinyl substituent lie on opposite sides of the plane of the benzofuran fragment. The crystal structure exhibits aromatic [pi]-[pi] interactions between the benzene rings of adjacent molecules [centroid-centroid distance = 3.643 (2) Å] and nonclassical C-H...O hydrogen bonds.

Comment top

The benzofuran ring system has attracted considerable interest in view of their biological and pharmacological properties (Howlett et al., 1999; Ward, 1997). This work is related to our communications on the synthesis and structures of alkyl 2-(5-bromo-3-methylsulfinyl-1-benzofuran-2-yl)acetate analogues, viz. butyl 2-(5-bromo-3-methylsulfinyl-1-benzofuran-2-yl)acetate (Choi et al., 2009a) and propyl 2-(5-bromo-3-methylsulfinyl-1-benzofuran-2-yl)acetate (Choi et al., 2009b). Here we report the crystal structure of the title compound, isoamyl 2-(5-bromo-3-methyllsulfinyl-1-benzofuran-2-yl)acetate (Fig. 1).

The benzofuran unit is essentially planar, with a mean deviation of 0.015 (1) Å from the least-squares plane defined by the nine constituent atoms. The crystal packing (Fig. 2) is stabilized by aromatic π···π interactions between the benzene rings from the adjacent molecules. The Cg···Cgii distance of 3.643 (2) Å (Cg is the centroid of C2-C7 benzene ring. symmetry code as in Fig. 2). The molecular packing is further stabilized by four different types of non-calssical C–H···O hydrogen bonds; the first between a benzene H atom and the S=O unit, the second between a benzene H atom and the C═O unit, the third between an H atom of the methylene group bonded to the carboxylate C atom and the S═O unit, the fourth between an H atom of the methylene group bonded to the carboxylate C atom and the furan O atom, respectively (Table 1 and Fig. 2; symmetry code as in Fig. 2).

Related literature top

For the crystal structures of similar alkyl 2-(5-bromo-3-methylsulfinyl-1-benzofuran-2-yl)acetate derivatives. see: Choi et al. (2009a,b). For the biological and pharmacological activity of benzofuran compounds, see: Howlett et al. (1999); Ward (1997).

Experimental top

The 77% 3-chloroperoxybenzoic acid (247 mg, 1.1 mmol) was added in small portions to a stirred solution of isoamyl 2-(5-bromo-3-methylsulfanyl-1-benzofuran-2-yl)acetate (371 mg, 1.0 mmol) in dichloromethane (30 ml) at 273 K. After being stirred for 4 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 colorless solid [yield 79%, m.p. 387-388 K; Rf = 0.61 (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 ethyl acetate at room temperature. Spectroscopic analysis: 1H NMR (CDCl3, 400 MHz) δ 0.91 (d, J = 6.6 Hz, 6H), 1.51-1.57 (m, 1H), 1.62-1.69 (m, 2H), 3.07 (s, 3H), 4.03 (s, 2H), 4.18 (t, J = 6.96 Hz, 2H), 7.39 (d, J = 8.8 Hz, 1H), 7.49 (dd, J = 8.8 Hz and J = 2.2 Hz, 1H), 8.09 (d, J = 1.84 Hz, 1H); EI-MS 388 [M+2], 386 [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, 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 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.
[Figure 2] Fig. 2. The π···π and C–H···O interactions (dotted lines) in the title compound. Cg denotes the ring centroids. [Symmetry code: (i) -x + 1, -y + 1, -z + 1; (ii) -x + 1, -y, -z + 1; (iii) -x + 2, -y + 1, -z + 1; (iv) -x + 2, -y, -z + 1.]
Isoamyl 2-(5-bromo-3-methylsulfinyl-1-benzofuran-2-yl)acetate top
Crystal data top
C16H19BrO4SZ = 2
Mr = 387.28F(000) = 396
Triclinic, P1Dx = 1.538 Mg m−3
Hall symbol: -p 1Mo Kα radiation, λ = 0.71073 Å
a = 8.3704 (4) ÅCell parameters from 5367 reflections
b = 10.2956 (6) Åθ = 2.1–28.2°
c = 10.524 (1) ŵ = 2.60 mm−1
α = 99.977 (1)°T = 173 K
β = 105.230 (1)°Block, colourless
γ = 100.681 (1)°0.60 × 0.40 × 0.10 mm
V = 836.04 (10) Å3
Data collection top
Bruker SMART CCD
diffractometer		3579 independent reflections
Radiation source: fine-focus sealed tube3304 reflections with I > 2σ(I)
graphiteRint = 0.024
Detector resolution: 10.0 pixels mm-1θmax = 27.0°, θmin = 2.6°
φ– and ω–scansh = −10→10
Absorption correction: multi-scan
SADABS (Sheldrick, 1999)		k = −13→13
Tmin = 0.302, Tmax = 0.769l = −13→13
7179 measured 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)] = 0.027Hydrogen site location: difference Fourier map
wR(F2) = 0.072H-atom parameters constrained
S = 1.04 w = 1/[σ2(Fo2) + (0.0362P)2 + 0.2834P]
where P = (Fo2 + 2Fc2)/3
3579 reflections(Δ/σ)max < 0.001
202 parametersΔρmax = 0.35 e Å−3
0 restraintsΔρmin = −0.59 e Å−3
Crystal data top
C16H19BrO4Sγ = 100.681 (1)°
Mr = 387.28V = 836.04 (10) Å3
Triclinic, P1Z = 2
a = 8.3704 (4) ÅMo Kα radiation
b = 10.2956 (6) ŵ = 2.60 mm−1
c = 10.524 (1) ÅT = 173 K
α = 99.977 (1)°0.60 × 0.40 × 0.10 mm
β = 105.230 (1)°
Data collection top
Bruker SMART CCD
diffractometer		3579 independent reflections
Absorption correction: multi-scan
SADABS (Sheldrick, 1999)		3304 reflections with I > 2σ(I)
Tmin = 0.302, Tmax = 0.769Rint = 0.024
7179 measured reflectionsθmax = 27.0°
Refinement top
R[F2 > 2σ(F2)] = 0.027H-atom parameters constrained
wR(F2) = 0.072Δρmax = 0.35 e Å−3
S = 1.04Δρmin = −0.59 e Å−3
3579 reflectionsAbsolute structure: ?
202 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

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) top
xyzUiso*/Ueq
Br0.09369 (2)0.119447 (19)0.255278 (19)0.03270 (8)
S0.83063 (5)0.46517 (4)0.59651 (5)0.02459 (11)
O10.81346 (14)0.07754 (11)0.46466 (12)0.0215 (2)
O21.24425 (15)0.21464 (13)0.82349 (12)0.0254 (3)
O31.00246 (16)0.27962 (14)0.82283 (14)0.0330 (3)
O40.73464 (19)0.52767 (13)0.49185 (15)0.0335 (3)
C10.7776 (2)0.28864 (16)0.52535 (17)0.0202 (3)
C20.6130 (2)0.20245 (16)0.44185 (16)0.0195 (3)
C30.4469 (2)0.21889 (17)0.39790 (17)0.0222 (3)
H30.42140.30250.41950.027*
C40.3225 (2)0.10378 (18)0.32050 (17)0.0230 (3)
C50.3554 (2)−0.02394 (17)0.28541 (18)0.0244 (3)
H50.2667−0.09780.23270.029*
C60.5200 (2)−0.04033 (17)0.32914 (18)0.0237 (3)
H60.5453−0.12400.30690.028*
C70.6445 (2)0.07386 (16)0.40746 (17)0.0202 (3)
C80.8916 (2)0.20979 (16)0.53584 (17)0.0203 (3)
C91.0744 (2)0.23516 (17)0.61405 (18)0.0225 (3)
H9A1.13710.31910.60230.027*
H9B1.12060.16190.57900.027*
C101.0990 (2)0.24522 (16)0.76378 (18)0.0226 (3)
C111.2757 (2)0.2174 (2)0.96764 (19)0.0344 (4)
H11A1.18450.15270.98030.041*
H11B1.28020.30731.01740.041*
C121.4438 (2)0.18093 (19)1.01854 (19)0.0301 (4)
H12A1.44170.09730.95840.036*
H12B1.45310.16251.10720.036*
C131.6038 (2)0.28719 (19)1.03000 (19)0.0290 (4)
H131.59490.30640.94070.035*
C141.6262 (3)0.4197 (2)1.1307 (2)0.0483 (6)
H14A1.53160.45881.10040.072*
H14B1.73040.48191.13730.072*
H14C1.63070.40181.21800.072*
C151.7591 (3)0.2284 (3)1.0724 (2)0.0476 (6)
H15A1.85980.29221.07460.071*
H15B1.74400.14491.00850.071*
H15C1.77100.21111.16080.071*
C160.7171 (3)0.4627 (2)0.7195 (2)0.0363 (5)
H16A0.73070.55400.76800.055*
H16B0.76190.41090.78190.055*
H16C0.59820.42170.67430.055*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br0.01875 (11)0.04364 (13)0.03281 (12)0.00906 (8)0.00246 (8)0.00820 (8)
S0.0252 (2)0.01788 (19)0.0290 (2)0.00410 (15)0.00857 (18)0.00199 (16)
O10.0193 (6)0.0199 (5)0.0249 (6)0.0061 (4)0.0063 (5)0.0035 (5)
O20.0212 (6)0.0340 (6)0.0203 (6)0.0080 (5)0.0042 (5)0.0061 (5)
O30.0244 (7)0.0439 (8)0.0290 (7)0.0089 (6)0.0098 (6)0.0008 (6)
O40.0438 (8)0.0243 (6)0.0391 (8)0.0130 (6)0.0164 (6)0.0136 (6)
C10.0208 (8)0.0177 (7)0.0213 (8)0.0042 (6)0.0060 (6)0.0038 (6)
C20.0215 (8)0.0201 (7)0.0174 (8)0.0050 (6)0.0060 (6)0.0055 (6)
C30.0231 (8)0.0240 (8)0.0213 (8)0.0084 (6)0.0067 (7)0.0076 (6)
C40.0171 (8)0.0325 (9)0.0201 (8)0.0066 (6)0.0048 (6)0.0086 (7)
C50.0221 (8)0.0270 (8)0.0207 (8)0.0005 (6)0.0060 (7)0.0034 (7)
C60.0265 (9)0.0201 (8)0.0243 (9)0.0047 (6)0.0100 (7)0.0020 (6)
C70.0196 (8)0.0227 (8)0.0200 (8)0.0068 (6)0.0072 (6)0.0061 (6)
C80.0208 (8)0.0192 (7)0.0206 (8)0.0039 (6)0.0070 (6)0.0037 (6)
C90.0190 (8)0.0235 (8)0.0250 (9)0.0063 (6)0.0063 (7)0.0053 (6)
C100.0178 (8)0.0192 (7)0.0264 (9)−0.0002 (6)0.0053 (7)0.0015 (6)
C110.0268 (10)0.0529 (12)0.0216 (9)0.0053 (8)0.0065 (7)0.0102 (8)
C120.0317 (10)0.0338 (9)0.0228 (9)0.0054 (7)0.0037 (7)0.0109 (7)
C130.0263 (9)0.0348 (10)0.0224 (9)0.0052 (7)0.0021 (7)0.0080 (7)
C140.0529 (14)0.0353 (11)0.0417 (13)0.0034 (10)0.0010 (11)−0.0012 (10)
C150.0338 (12)0.0684 (16)0.0400 (13)0.0200 (11)0.0044 (10)0.0130 (11)
C160.0512 (12)0.0335 (10)0.0317 (11)0.0175 (9)0.0215 (10)0.0054 (8)
Geometric parameters (Å, °) top
Br—C41.9047 (17)C9—C101.517 (2)
S—O41.4984 (14)C9—H9A0.9700
S—C11.7651 (16)C9—H9B0.9700
S—C161.796 (2)C11—C121.509 (3)
O1—C71.374 (2)C11—H11A0.9700
O1—C81.3791 (19)C11—H11B0.9700
O2—C101.335 (2)C12—C131.527 (3)
O2—C111.464 (2)C12—H12A0.9700
O3—C101.208 (2)C12—H12B0.9700
C1—C81.358 (2)C13—C141.523 (3)
C1—C21.449 (2)C13—C151.528 (3)
C2—C31.397 (2)C13—H130.9800
C2—C71.403 (2)C14—H14A0.9600
C3—C41.384 (2)C14—H14B0.9600
C3—H30.9300C14—H14C0.9600
C4—C51.400 (2)C15—H15A0.9600
C5—C61.385 (2)C15—H15B0.9600
C5—H50.9300C15—H15C0.9600
C6—C71.381 (2)C16—H16A0.9600
C6—H60.9300C16—H16B0.9600
C8—C91.484 (2)C16—H16C0.9600
O4—S—C1106.60 (8)O2—C10—C9111.26 (14)
O4—S—C16105.52 (9)O2—C11—C12107.96 (15)
C1—S—C1698.25 (9)O2—C11—H11A110.1
C7—O1—C8106.47 (12)C12—C11—H11A110.1
C10—O2—C11114.98 (14)O2—C11—H11B110.1
C8—C1—C2107.39 (14)C12—C11—H11B110.1
C8—C1—S124.39 (13)H11A—C11—H11B108.4
C2—C1—S128.16 (12)C11—C12—C13116.26 (16)
C3—C2—C7119.64 (15)C11—C12—H12A108.2
C3—C2—C1135.88 (15)C13—C12—H12A108.2
C7—C2—C1104.44 (14)C11—C12—H12B108.2
C4—C3—C2116.29 (15)C13—C12—H12B108.2
C4—C3—H3121.9H12A—C12—H12B107.4
C2—C3—H3121.9C14—C13—C12112.39 (18)
C3—C4—C5123.73 (15)C14—C13—C15109.96 (18)
C3—C4—Br118.49 (13)C12—C13—C15108.72 (17)
C5—C4—Br117.77 (13)C14—C13—H13108.6
C6—C5—C4120.00 (15)C12—C13—H13108.6
C6—C5—H5120.0C15—C13—H13108.6
C4—C5—H5120.0C13—C14—H14A109.5
C7—C6—C5116.59 (15)C13—C14—H14B109.5
C7—C6—H6121.7H14A—C14—H14B109.5
C5—C6—H6121.7C13—C14—H14C109.5
O1—C7—C6125.46 (15)H14A—C14—H14C109.5
O1—C7—C2110.78 (14)H14B—C14—H14C109.5
C6—C7—C2123.75 (15)C13—C15—H15A109.5
C1—C8—O1110.91 (14)C13—C15—H15B109.5
C1—C8—C9133.32 (15)H15A—C15—H15B109.5
O1—C8—C9115.60 (14)C13—C15—H15C109.5
C8—C9—C10111.79 (14)H15A—C15—H15C109.5
C8—C9—H9A109.3H15B—C15—H15C109.5
C10—C9—H9A109.3S—C16—H16A109.5
C8—C9—H9B109.3S—C16—H16B109.5
C10—C9—H9B109.3H16A—C16—H16B109.5
H9A—C9—H9B107.9S—C16—H16C109.5
O3—C10—O2123.95 (17)H16A—C16—H16C109.5
O3—C10—C9124.76 (16)H16B—C16—H16C109.5
O4—S—C1—C8137.41 (15)C1—C2—C7—O10.44 (18)
C16—S—C1—C8−113.60 (16)C3—C2—C7—C61.1 (2)
O4—S—C1—C2−39.41 (17)C1—C2—C7—C6179.05 (16)
C16—S—C1—C269.57 (17)C2—C1—C8—O10.16 (19)
C8—C1—C2—C3177.04 (18)S—C1—C8—O1−177.22 (11)
S—C1—C2—C3−5.7 (3)C2—C1—C8—C9−174.86 (17)
C8—C1—C2—C7−0.36 (18)S—C1—C8—C97.8 (3)
S—C1—C2—C7176.90 (13)C7—O1—C8—C10.11 (18)
C7—C2—C3—C4−0.5 (2)C7—O1—C8—C9176.10 (14)
C1—C2—C3—C4−177.59 (18)C1—C8—C9—C1073.0 (2)
C2—C3—C4—C5−0.2 (2)O1—C8—C9—C10−101.84 (16)
C2—C3—C4—Br−179.23 (12)C11—O2—C10—O33.6 (2)
C3—C4—C5—C60.3 (3)C11—O2—C10—C9−178.09 (14)
Br—C4—C5—C6179.34 (13)C8—C9—C10—O3−26.2 (2)
C4—C5—C6—C70.3 (2)C8—C9—C10—O2155.53 (14)
C8—O1—C7—C6−178.93 (16)C10—O2—C11—C12−179.92 (14)
C8—O1—C7—C2−0.35 (17)O2—C11—C12—C1370.7 (2)
C5—C6—C7—O1177.40 (15)C11—C12—C13—C1462.3 (2)
C5—C6—C7—C2−1.0 (2)C11—C12—C13—C15−175.75 (17)
C3—C2—C7—O1−177.47 (14)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C3—H3···O4i0.932.563.437 (2)157
C5—H5···O3ii0.932.513.383 (2)157
C9—H9A···O4iii0.972.263.192 (2)162
C9—H9B···O1iv0.972.613.541 (2)160
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+1, −y, −z+1; (iii) −x+2, −y+1, −z+1; (iv) −x+2, −y, −z+1.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C3—H3···O4i0.932.563.437 (2)157
C5—H5···O3ii0.932.513.383 (2)157
C9—H9A···O4iii0.972.263.192 (2)162
C9—H9B···O1iv0.972.613.541 (2)160
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+1, −y, −z+1; (iii) −x+2, −y+1, −z+1; (iv) −x+2, −y, −z+1.
Acknowledgements top

No acknowledgements.

references
References top

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