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Acta Cryst. (2009). E65, o563    [ doi:10.1107/S1600536809005376 ]

2-(5-Bromo-3-methylsulfanyl-1-benzofuran-2-yl)acetic acid

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

Abstract top

The title compound, C11H9BrO3S, was prepared by alkaline hydrolysis of ethyl 2-(5-bromo-3-methylsulfanyl-1-benzofuran-2-yl)acetate. In the crystal structure, the carboxyl groups are involved in intermolecular O-H...O hydrogen bonds, which link the molecules into centrosymmetric dimers. These dimers are further packed into stacks along the c axis by weak C-H...[pi] interactions. In addition, the stacked molecules exhibit a Br...S interaction of 3.4787 (7) Å.

Comment top

As a part of our ongoing studies on the synthesis and structures of 2-(3-methylsulfanyl-1-benzofuran-2-yl)acetic acid analogues, the crystal structure of 2-(5,7-dimethyl-3-methylsulfanyl-1-benzofuran-2-yl)acetic acid (Choi et al., 2008a) and 2-(6,7-dimethyl-3-methylsulfanyl-1-benzofuran-2-yl)acetic acid (Choi et al., 2008b) have been described in the literature. Here we report the crystal structure of the title compound, 2-(5-bromo-3-methylsulfanyl-1-benzofuran-2-yl)acetic acid (Fig. 1).

The benzofuran unit is essentially planar, with a mean deviation of 0.011 (2) Å from the least-squares plane defined by the nine constituent atoms. In crystal structure, the carboxyl groups are involved in intermolecular O—H···O hydrogen bonds (Fig. 2 and Table 1; symmetry code as in Fig. 2), which link the molecules into centrosymmetric dimers. These dimers are further packed into stacks along the c–axis by weak C—H···π interactions, with a C11—H11C···Cgii separation of 3.22 Å (Fig. 2 and Table 1; Cg is the centroid of the C2–C7 benzene ring, symmetry code as in Fig. 2). Additionally, the stacked molecules exhibit a Br···S interaction, with a C4—Br···Siii distance of 3.4787 (7) Å (symmetry code as in Fig. 2).

Related literature top

For the crystal structures of similar 2-(3-methylsulfanyl-1-benzofuran-2-yl)acetic acid derivatives, see: Choi et al. (2008a,b). Cg is the centroid of the C2–C7 benzene ring

Experimental top

Ethyl 2-(5-bromo-3-methylsulfanyl-1-benzofuran-2-yl)acetate (329 mg, 1.0 mmol) was added to a solution of potassium hydroxide (337 mg, 6.0 mmol) in water (25 ml) and methanol (25 ml), and the mixture was refluxed for 5h, then cooled. Water was added, and the solution was extracted with dichloromethane. The aqueous layer was acidified to pH 1 with concentrated hydrochloric acid and then extracted with chloroform, 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 88%, m.p. 444-445 K; Rf = 0.56 (ethyl acetate)]. Single crystals suitable for X-ray diffraction were prepared by evaporation of a solution of the title compound in benzene at room temperature. Spectroscopic analysis: 1H NMR (CDCl3, 400 MHz) δ 2.32 (s, 3H), 4.04 (s, 2H), 7.33 (d, J = 8.8 Hz, 1H), 7.41 (dd, J = 8.8 Hz and J = 1.84 Hz, 1H), 7.77 (d, J = 2.2 Hz, 1H), 10.03 (s, 1H); EI-MS 302 [M+2], 300 [M+].

Refinement top

The H atom of O3 was positioned in a difference Fourier map and refined freely. Other H atoms were geometrically positioned and refined using a riding model, with C—H = 0.93 (aromatic), 0.97 (methylene), and 0.96 Å (methyl) H atoms, respectively, and with Uiso(H) = 1.2Ueq(C) (aromatic, methylene), and 1.5Ueq(C) (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 displacement ellipsoids drawn at the 50% probability level.
[Figure 2] Fig. 2. C—H···π and Br···S interactions, and hydrogen bonds (dotted lines) in the title compound. Cg denotes the ring centroid. [Symmetry code: (i) -x+1, -y+1, -z; (ii) x, y+1, z-1; (iii) x-1, -y+1/2, z+1/2; (iv) x+1, -y+1/2, z-1/2; (v) x, y, z+1.]
2-(5-Bromo-3-methylsulfanyl-1-benzofuran-2-yl)acetic acid top
Crystal data top
C11H9BrO3SF(000) = 600
Mr = 301.15Dx = 1.754 Mg m−3
Monoclinic, P21/cMelting point = 404–405 K
Hall symbol: -P 2ybcMo Kα radiation, λ = 0.71073 Å
a = 4.9976 (4) ÅCell parameters from 3612 reflections
b = 29.740 (2) Åθ = 2.6–28.3°
c = 7.6780 (6) ŵ = 3.78 mm−1
β = 92.401 (1)°T = 100 K
V = 1140.17 (15) Å3Block, colorless
Z = 40.50 × 0.30 × 0.15 mm
Data collection top
Bruker SMART CCD
diffractometer		2483 independent reflections
Radiation source: fine-focus sealed tube2178 reflections with I > 2σ(I)
graphiteRint = 0.028
Detector resolution: 10.0 pixels mm-1θmax = 27.0°, θmin = 1.4°
φ and ω scansh = −6→6
Absorption correction: multi-scan
(SADABS; Sheldrick, 2000)		k = −37→19
Tmin = 0.261, Tmax = 0.562l = −9→9
6872 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 atoms treated by a mixture of independent and constrained refinement
S = 1.11 w = 1/[σ2(Fo2) + (0.0331P)2 + 0.6004P]
where P = (Fo2 + 2Fc2)/3
2483 reflections(Δ/σ)max < 0.001
150 parametersΔρmax = 0.32 e Å−3
0 restraintsΔρmin = −0.56 e Å−3
Crystal data top
C11H9BrO3SV = 1140.17 (15) Å3
Mr = 301.15Z = 4
Monoclinic, P21/cMo Kα radiation
a = 4.9976 (4) ŵ = 3.78 mm−1
b = 29.740 (2) ÅT = 100 K
c = 7.6780 (6) Å0.50 × 0.30 × 0.15 mm
β = 92.401 (1)°
Data collection top
Bruker SMART CCD
diffractometer		2483 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2000)		2178 reflections with I > 2σ(I)
Tmin = 0.261, Tmax = 0.562Rint = 0.028
6872 measured reflectionsθmax = 27.0°
Refinement top
R[F2 > 2σ(F2)] = 0.027H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.072Δρmax = 0.32 e Å−3
S = 1.11Δρmin = −0.56 e Å−3
2483 reflectionsAbsolute structure: ?
150 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
Br−0.17879 (5)0.275363 (8)0.83802 (3)0.02932 (10)
S0.64485 (11)0.33767 (2)0.31284 (8)0.02358 (14)
O10.3933 (3)0.43916 (5)0.5972 (2)0.0218 (3)
O20.7696 (3)0.48334 (6)0.1003 (2)0.0262 (4)
O30.3598 (3)0.47267 (7)0.2002 (2)0.0276 (4)
H120.310 (7)0.4829 (12)0.107 (5)0.057 (11)*
C10.4952 (4)0.37501 (8)0.4556 (3)0.0180 (4)
C20.2974 (4)0.36437 (8)0.5820 (3)0.0179 (4)
C30.1697 (4)0.32509 (8)0.6316 (3)0.0191 (5)
H30.20480.29760.57970.023*
C4−0.0124 (5)0.32894 (8)0.7622 (3)0.0200 (5)
C5−0.0721 (5)0.36984 (8)0.8405 (3)0.0235 (5)
H5−0.19870.37080.92580.028*
C60.0554 (5)0.40921 (8)0.7925 (3)0.0234 (5)
H60.01900.43680.84380.028*
C70.2403 (4)0.40497 (8)0.6634 (3)0.0190 (5)
C80.5450 (4)0.41944 (8)0.4709 (3)0.0198 (5)
C90.7313 (5)0.44956 (8)0.3800 (3)0.0226 (5)
H9A0.89110.43260.35540.027*
H9B0.78470.47370.45880.027*
C100.6219 (4)0.47002 (8)0.2118 (3)0.0192 (5)
C110.3591 (6)0.32394 (13)0.1715 (4)0.0455 (8)
H11A0.22120.31100.23910.068*
H11B0.41130.30270.08500.068*
H11C0.29250.35080.11520.068*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br0.03467 (16)0.02278 (15)0.03138 (16)−0.00670 (10)0.01158 (10)0.00524 (10)
S0.0194 (3)0.0267 (3)0.0250 (3)0.0028 (2)0.0052 (2)−0.0036 (3)
O10.0273 (8)0.0150 (8)0.0234 (8)−0.0025 (7)0.0048 (7)0.0025 (7)
O20.0198 (8)0.0332 (10)0.0260 (9)0.0008 (7)0.0053 (7)0.0115 (8)
O30.0169 (8)0.0398 (11)0.0262 (9)−0.0008 (7)0.0004 (7)0.0135 (8)
C10.0180 (10)0.0203 (11)0.0159 (10)0.0017 (9)0.0022 (8)0.0024 (9)
C20.0176 (10)0.0206 (11)0.0156 (10)0.0014 (9)0.0013 (8)0.0023 (9)
C30.0234 (11)0.0161 (11)0.0178 (11)−0.0001 (9)0.0010 (9)−0.0008 (9)
C40.0234 (11)0.0186 (11)0.0180 (11)−0.0037 (9)0.0007 (9)0.0048 (9)
C50.0263 (12)0.0265 (13)0.0183 (11)0.0000 (10)0.0066 (9)0.0001 (10)
C60.0294 (12)0.0201 (12)0.0210 (12)0.0019 (10)0.0043 (9)−0.0021 (10)
C70.0208 (11)0.0162 (11)0.0199 (11)−0.0012 (9)0.0003 (9)0.0037 (9)
C80.0194 (10)0.0224 (12)0.0176 (11)0.0014 (9)0.0010 (8)0.0036 (9)
C90.0196 (11)0.0232 (12)0.0250 (12)−0.0020 (9)0.0003 (9)0.0084 (10)
C100.0201 (11)0.0149 (11)0.0226 (11)0.0002 (9)0.0027 (9)0.0017 (9)
C110.0288 (14)0.073 (2)0.0341 (15)0.0025 (15)−0.0009 (12)−0.0262 (16)
Geometric parameters (Å, °) top
Br—C41.900 (2)C3—H30.9300
Br—Si3.4787 (7)C4—C51.395 (3)
S—C11.750 (2)C5—C61.390 (3)
S—C111.804 (3)C5—H50.9300
O1—C71.382 (3)C6—C71.389 (3)
O1—C81.386 (3)C6—H60.9300
O2—C101.220 (3)C8—C91.487 (3)
O3—C101.312 (3)C9—C101.509 (3)
O3—H120.81 (4)C9—H9A0.9700
C1—C81.349 (3)C9—H9B0.9700
C1—C21.449 (3)C11—H11A0.9600
C2—C31.392 (3)C11—H11B0.9600
C2—C71.395 (3)C11—H11C0.9600
C3—C41.387 (3)
C4—Br—Si155.04 (7)O1—C7—C6126.2 (2)
C1—S—C1199.90 (12)O1—C7—C2110.21 (19)
C7—O1—C8105.87 (17)C6—C7—C2123.6 (2)
C10—O3—H12111 (3)C1—C8—O1111.8 (2)
C8—C1—C2106.5 (2)C1—C8—C9131.8 (2)
C8—C1—S126.44 (18)O1—C8—C9116.4 (2)
C2—C1—S127.04 (18)C8—C9—C10115.67 (19)
C3—C2—C7120.0 (2)C8—C9—H9A108.4
C3—C2—C1134.4 (2)C10—C9—H9A108.4
C7—C2—C1105.6 (2)C8—C9—H9B108.4
C4—C3—C2116.8 (2)C10—C9—H9B108.4
C4—C3—H3121.6H9A—C9—H9B107.4
C2—C3—H3121.6O2—C10—O3124.4 (2)
C3—C4—C5122.8 (2)O2—C10—C9121.6 (2)
C3—C4—Br117.46 (18)O3—C10—C9114.0 (2)
C5—C4—Br119.68 (17)S—C11—H11A109.5
C6—C5—C4120.8 (2)S—C11—H11B109.5
C6—C5—H5119.6H11A—C11—H11B109.5
C4—C5—H5119.6S—C11—H11C109.5
C7—C6—C5116.0 (2)H11A—C11—H11C109.5
C7—C6—H6122.0H11B—C11—H11C109.5
C5—C6—H6122.0
C11—S—C1—C8−113.0 (2)C5—C6—C7—O1−178.9 (2)
C11—S—C1—C267.9 (2)C5—C6—C7—C20.9 (4)
C8—C1—C2—C3−178.7 (2)C3—C2—C7—O1178.60 (19)
S—C1—C2—C30.5 (4)C1—C2—C7—O1−1.1 (2)
C8—C1—C2—C70.9 (2)C3—C2—C7—C6−1.3 (4)
S—C1—C2—C7−179.91 (17)C1—C2—C7—C6179.1 (2)
C7—C2—C3—C40.2 (3)C2—C1—C8—O1−0.4 (3)
C1—C2—C3—C4179.8 (2)S—C1—C8—O1−179.63 (16)
C2—C3—C4—C51.1 (3)C2—C1—C8—C9178.6 (2)
C2—C3—C4—Br−177.68 (16)S—C1—C8—C9−0.6 (4)
Si—Br—C4—C3−12.5 (3)C7—O1—C8—C1−0.2 (2)
Si—Br—C4—C5168.77 (12)C7—O1—C8—C9−179.39 (19)
C3—C4—C5—C6−1.4 (4)C1—C8—C9—C1087.7 (3)
Br—C4—C5—C6177.28 (18)O1—C8—C9—C10−93.3 (3)
C4—C5—C6—C70.4 (3)C8—C9—C10—O2−157.1 (2)
C8—O1—C7—C6−179.3 (2)C8—C9—C10—O324.1 (3)
C8—O1—C7—C20.8 (2)
Symmetry codes: (i) x−1, −y+1/2, z+1/2.
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O3—H12···O2ii0.81 (4)1.91 (4)2.707 (2)169 (4)
C11—H11C···Cgiii0.963.223.904 (3)129
Symmetry codes: (ii) −x+1, −y+1, −z; (iii) x, y, z−1.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O3—H12···O2i0.81 (4)1.91 (4)2.707 (2)169 (4)
C11—H11C···Cgii0.963.223.904 (3)129
Symmetry codes: (i) −x+1, −y+1, −z; (ii) x, y, z−1.
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, o1598.

Choi, H. D., Seo, P. J., Son, B. W. & Lee, U. (2008b). Acta Cryst. E64, o1688.

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

Sheldrick, G. M. (2000). SADABS. University of Göttingen, Germany.

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