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Acta Cryst. (2009). E65, o998    [ doi:10.1107/S1600536809012124 ]

2-(3-Methylsulfanyl-5-propyl-1-benzofuran-2-yl)acetic acid

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

Abstract top

The title compound, C14H16O3S, was prepared by alkaline hydrolysis of ethyl 2-(3-methylsulfanyl-5-propyl-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 a axis by weak C-H...[pi] interactions.

Comment top

This work is related to our communications on the synthesis and structure of 2-(3-methylsulfanyl-1-benzofuran-2-yl)acetic acid derivatives, viz. 2-(5-ethyl-3-methylsulfanyl-1-benzofuran-2-yl)acetic acid (Seo et al., 2007) and 2-(5,7-dimethyl-3-methylsulfanyl-1-benzofuran-2-yl)acetic acid (Choi et al., 2008). Here we report the crystal structure of the title compound, 2-(3-methylsulfanyl-5-propyl-1-benzofuran-2-yl)acetic acid (Fig. 1).

The benzofuran unit is essentially planar, with a mean deviation of 0.005 (3) Å from the least-squares plane defined by the nine constituent atoms. In the 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 a-axis by weak C—H···π interactions, with a C12—H12A···Cgii separation of 3.04 Å (Fig. 2 and Table 1; Cg is the centroid of the C1/C2/C7/O1/C8 furan ring, 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: Seo et al. (2007); Choi et al. (2008). Cg is the centroid of the C1/C2/C7/O1/C8 furan ring.

Experimental top

Ethyl 2-(3-methylsulfanyl-5-propyl-1-benzofuran-2-yl)acetate (334 mg, 1.2 mmol) was added to a solution of potassium hydroxide (337 mg, 6.0 mmol) in water (20 ml) and methanol (20 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 84%, m.p. 395-396 K; Rf = 0.78 (ethyl acetate)]. Single crystals suitable for X-ray diffraction were prepared by evaporation of a solution of the title compound in diisopropyl ether at room temperature. Spectroscopic analysis: 1H NMR (CDCl3, 400 MHz) δ 0.96 (t, J = 7.32 Hz, 3H), 1.64-1.73 (m, 2H), 2.33 (s, 3H), 2.70 (t, J = 7.68 Hz, 2H), 4.03 (s, 2H), 7.13 (dd, J = 8.44 Hz and 1.44 Hz, 1H), 7.36 (d, J = 8.44 Hz, 1H), 7.43 (s, 1H), 10.02 (s, 1H); EI-MS 264 [M+].

Refinement top

All H atoms were geometrically positioned and refined using a riding model, with C—H = 0.93 (aromatic), 0.97 (methylene), 0.96 Å (methyl) H atoms, and O—H = 0.82 respectively, and with Uiso(H) = 1.2Ueq(C) (aromatic, methylene), 1.5Ueq(C) (methyl), and 1.5Ueq(O) 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. O—H···O and C—H···π interactions (dotted lines) in the title compound. Cg denotes the ring centroid. [Symmetry code: (i) -x, -y, -z+1; (ii) x-1, y, z; (iii) x+1, y, z; (iv) -x+1, -y, -z+1.]
2-(3-Methylsulfanyl-5-propyl-1-benzofuran-2-yl)acetic acid top
Crystal data top
C14H16O3SZ = 2
Mr = 264.33F(000) = 280
Triclinic, P1Dx = 1.260 Mg m−3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71069 Å
a = 5.1727 (6) ÅCell parameters from 1161 reflections
b = 8.173 (1) Åθ = 2.5–22.1°
c = 16.614 (2) ŵ = 0.23 mm−1
α = 94.321 (2)°T = 298 K
β = 95.831 (2)°Block, colorless
γ = 91.110 (2)°0.20 × 0.20 × 0.05 mm
V = 696.50 (14) Å3
Data collection top
Bruker SMART CCD
diffractometer		1425 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.049
graphiteθmax = 25.0°, θmin = 2.5°
Detector resolution: 10.0 pixels mm-1h = −5→6
φ and ω scansk = −9→9
3658 measured reflectionsl = −19→14
2389 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)] = 0.059Hydrogen site location: difference Fourier map
wR(F2) = 0.151H-atom parameters constrained
S = 1.06 w = 1/[σ2(Fo2) + (0.0531P)2 + 0.2044P]
where P = (Fo2 + 2Fc2)/3
2389 reflections(Δ/σ)max < 0.001
165 parametersΔρmax = 0.21 e Å−3
0 restraintsΔρmin = −0.24 e Å−3
Crystal data top
C14H16O3Sγ = 91.110 (2)°
Mr = 264.33V = 696.50 (14) Å3
Triclinic, P1Z = 2
a = 5.1727 (6) ÅMo Kα radiation
b = 8.173 (1) ŵ = 0.23 mm−1
c = 16.614 (2) ÅT = 298 K
α = 94.321 (2)°0.20 × 0.20 × 0.05 mm
β = 95.831 (2)°
Data collection top
Bruker SMART CCD
diffractometer		1425 reflections with I > 2σ(I)
3658 measured reflectionsRint = 0.049
2389 independent reflectionsθmax = 25.0°
Refinement top
R[F2 > 2σ(F2)] = 0.059H-atom parameters constrained
wR(F2) = 0.151Δρmax = 0.21 e Å−3
S = 1.06Δρmin = −0.24 e Å−3
2389 reflectionsAbsolute structure: ?
165 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
S−0.09603 (19)0.20796 (12)0.21468 (7)0.0768 (4)
O10.1105 (4)0.5482 (3)0.39156 (13)0.0636 (6)
O20.1260 (5)0.1733 (3)0.45463 (16)0.0851 (9)
H2O0.16070.08910.47690.128*
O3−0.2757 (4)0.0916 (3)0.46894 (16)0.0785 (8)
C10.0362 (6)0.3712 (4)0.2809 (2)0.0520 (8)
C20.2351 (6)0.4892 (4)0.26600 (19)0.0516 (8)
C30.3818 (6)0.5128 (4)0.2021 (2)0.0591 (9)
H30.35900.44250.15520.071*
C40.5633 (6)0.6423 (4)0.2089 (2)0.0627 (10)
C50.5902 (7)0.7445 (4)0.2808 (3)0.0711 (10)
H50.70940.83220.28520.085*
C60.4507 (7)0.7226 (4)0.3450 (2)0.0708 (10)
H60.47520.79100.39260.085*
C70.2718 (6)0.5937 (4)0.3353 (2)0.0556 (8)
C8−0.0298 (6)0.4115 (4)0.3551 (2)0.0546 (8)
C90.7208 (8)0.6706 (5)0.1400 (2)0.0824 (12)
H9A0.88180.72780.16180.099*
H9B0.76530.56490.11530.099*
C100.5895 (10)0.7662 (7)0.0762 (3)0.1197 (18)
H10A0.54330.87130.10110.144*
H10B0.42930.70840.05420.144*
C110.7458 (12)0.7960 (8)0.0082 (3)0.146 (2)
H11A0.87350.88170.02530.219*
H11B0.63350.8284−0.03710.219*
H11C0.83140.6972−0.00750.219*
C12−0.2179 (6)0.3359 (4)0.4048 (2)0.0619 (9)
H12A−0.37610.30450.37020.074*
H12B−0.26200.41760.44630.074*
C13−0.1180 (6)0.1878 (4)0.44510 (19)0.0545 (8)
C140.1689 (8)0.0703 (5)0.2223 (3)0.1078 (16)
H14A0.32700.12780.21460.162*
H14B0.1370−0.01920.18130.162*
H14C0.18470.02840.27490.162*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
S0.0644 (7)0.0620 (6)0.1009 (8)−0.0190 (5)0.0062 (5)−0.0057 (5)
O10.0738 (16)0.0557 (14)0.0620 (15)−0.0043 (12)0.0080 (12)0.0099 (11)
O20.0554 (17)0.0877 (18)0.120 (2)0.0049 (13)0.0086 (14)0.0595 (16)
O30.0556 (15)0.0722 (16)0.113 (2)−0.0081 (12)0.0101 (13)0.0463 (15)
C10.0513 (19)0.0419 (17)0.063 (2)−0.0047 (14)0.0008 (16)0.0153 (15)
C20.055 (2)0.0433 (17)0.057 (2)−0.0015 (15)−0.0005 (16)0.0152 (16)
C30.062 (2)0.0521 (19)0.064 (2)−0.0027 (16)0.0043 (17)0.0104 (16)
C40.060 (2)0.054 (2)0.075 (3)−0.0056 (17)0.0014 (18)0.0213 (19)
C50.070 (2)0.049 (2)0.095 (3)−0.0111 (18)0.004 (2)0.017 (2)
C60.088 (3)0.0472 (19)0.075 (3)−0.0126 (19)0.003 (2)0.0014 (18)
C70.062 (2)0.0447 (17)0.061 (2)−0.0007 (15)0.0056 (17)0.0111 (17)
C80.055 (2)0.0487 (18)0.061 (2)−0.0023 (15)0.0006 (16)0.0183 (16)
C90.078 (3)0.079 (3)0.095 (3)−0.012 (2)0.016 (2)0.030 (2)
C100.135 (4)0.134 (4)0.105 (4)0.020 (3)0.041 (3)0.056 (3)
C110.190 (6)0.151 (5)0.107 (4)−0.005 (5)0.046 (4)0.042 (4)
C120.055 (2)0.060 (2)0.075 (2)0.0041 (16)0.0076 (17)0.0286 (18)
C130.045 (2)0.058 (2)0.063 (2)0.0015 (16)0.0080 (16)0.0191 (16)
C140.080 (3)0.059 (2)0.183 (5)−0.007 (2)0.031 (3)−0.020 (3)
Geometric parameters (Å, °) top
S—C11.746 (3)C6—H60.9300
S—C141.791 (4)C8—C121.493 (4)
O1—C71.381 (4)C9—C101.482 (5)
O1—C81.385 (4)C9—H9A0.9700
O2—C131.265 (3)C9—H9B0.9700
O2—H2O0.8200C10—C111.487 (6)
O3—C131.237 (4)C10—H10A0.9700
C1—C81.332 (4)C10—H10B0.9700
C1—C21.448 (4)C11—H11A0.9600
C2—C71.376 (4)C11—H11B0.9600
C2—C31.388 (4)C11—H11C0.9600
C3—C41.392 (4)C12—C131.501 (4)
C3—H30.9300C12—H12A0.9700
C4—C51.399 (5)C12—H12B0.9700
C4—C91.499 (5)C14—H14A0.9600
C5—C61.368 (5)C14—H14B0.9600
C5—H50.9300C14—H14C0.9600
C6—C71.377 (4)
C1—S—C1499.71 (17)C10—C9—H9B108.6
C7—O1—C8105.5 (2)C4—C9—H9B108.6
C13—O2—H2O109.5H9A—C9—H9B107.6
C8—C1—C2106.9 (3)C9—C10—C11114.8 (4)
C8—C1—S126.0 (2)C9—C10—H10A108.6
C2—C1—S127.1 (3)C11—C10—H10A108.6
C7—C2—C3119.6 (3)C9—C10—H10B108.6
C7—C2—C1105.4 (3)C11—C10—H10B108.6
C3—C2—C1135.0 (3)H10A—C10—H10B107.5
C2—C3—C4119.6 (3)C10—C11—H11A109.5
C2—C3—H3120.2C10—C11—H11B109.5
C4—C3—H3120.2H11A—C11—H11B109.5
C3—C4—C5118.0 (3)C10—C11—H11C109.5
C3—C4—C9120.2 (3)H11A—C11—H11C109.5
C5—C4—C9121.8 (3)H11B—C11—H11C109.5
C6—C5—C4123.6 (3)C8—C12—C13114.0 (3)
C6—C5—H5118.2C8—C12—H12A108.8
C4—C5—H5118.2C13—C12—H12A108.8
C5—C6—C7116.4 (3)C8—C12—H12B108.8
C5—C6—H6121.8C13—C12—H12B108.8
C7—C6—H6121.8H12A—C12—H12B107.7
C2—C7—C6122.9 (3)O3—C13—O2124.3 (3)
C2—C7—O1110.5 (3)O3—C13—C12118.8 (3)
C6—C7—O1126.6 (3)O2—C13—C12116.9 (3)
C1—C8—O1111.7 (3)S—C14—H14A109.5
C1—C8—C12132.2 (3)S—C14—H14B109.5
O1—C8—C12116.1 (3)H14A—C14—H14B109.5
C10—C9—C4114.6 (3)S—C14—H14C109.5
C10—C9—H9A108.6H14A—C14—H14C109.5
C4—C9—H9A108.6H14B—C14—H14C109.5
C14—S—C1—C8−106.1 (3)C5—C6—C7—C21.1 (5)
C14—S—C1—C274.5 (3)C5—C6—C7—O1179.9 (3)
C8—C1—C2—C70.0 (3)C8—O1—C7—C2−0.2 (3)
S—C1—C2—C7179.5 (2)C8—O1—C7—C6−179.0 (3)
C8—C1—C2—C3179.1 (3)C2—C1—C8—O1−0.1 (3)
S—C1—C2—C3−1.4 (5)S—C1—C8—O1−179.6 (2)
C7—C2—C3—C4−0.3 (5)C2—C1—C8—C12−178.7 (3)
C1—C2—C3—C4−179.4 (3)S—C1—C8—C121.8 (5)
C2—C3—C4—C50.0 (5)C7—O1—C8—C10.2 (3)
C2—C3—C4—C9−179.2 (3)C7—O1—C8—C12179.0 (3)
C3—C4—C5—C60.9 (5)C3—C4—C9—C1083.8 (5)
C9—C4—C5—C6−179.8 (3)C5—C4—C9—C10−95.4 (5)
C4—C5—C6—C7−1.5 (5)C4—C9—C10—C11179.4 (5)
C3—C2—C7—C6−0.3 (5)C1—C8—C12—C1379.2 (4)
C1—C2—C7—C6179.0 (3)O1—C8—C12—C13−99.3 (3)
C3—C2—C7—O1−179.2 (3)C8—C12—C13—O3−160.9 (3)
C1—C2—C7—O10.1 (3)C8—C12—C13—O221.3 (5)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O2—H2O···O3i0.821.862.679 (3)174
C12—H12A···Cgii0.973.043.770 (3)133
Symmetry codes: (i) −x, −y, −z+1; (ii) x−1, y, z.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O2—H2O···O3i0.821.862.679 (3)174
C12—H12A···Cgii0.973.043.770 (3)133
Symmetry codes: (i) −x, −y, −z+1; (ii) x−1, y, z.
Acknowledgements top

No acknowledgement.

references
References top

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Bruker (2001). SAINT and SMART. Bruker AXS Inc., Madison, Wisconsin, USA.

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