organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

2-(3-Ethyl­sulfanyl-5-fluoro-1-benzo­furan-2-yl)acetic acid

aDepartment of Chemistry, Dongeui University, San 24 Kaya-dong Busanjin-gu, Busan 614-714, Republic of Korea, and bDepartment of Chemistry, Pukyong National University, 599-1 Daeyeon 3-dong, Nam-gu, Busan 608-737, Republic of Korea
*Correspondence e-mail: uklee@pknu.ac.kr

(Received 8 September 2009; accepted 11 September 2009; online 16 September 2009)

The title compound, C12H11FO3S, was prepared by alkaline hydrolysis of ethyl 2–(3–ethyl­sulfan­yl–5–fluoro–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 b axis by aromatic ππ inter­actions between the furan ring and the benzene ring of neighbouring benzofuran ring systems [centroid–centroid distance = 3.684 (5) Å].

Related literature

For the crystal structures of similar 2–(5–halo–1–benzofuran–2–­yl) acetic acid derivatives, see: Choi et al. (2009a[Choi, H. D., Seo, P. J., Son, B. W. & Lee, U. (2009a). Acta Cryst. E65, o563.],b[Choi, H. D., Seo, P. J., Son, B. W. & Lee, U. (2009b). Acta Cryst. E65, o1813.]). For the pharmacological properties of benzofuran compounds, see: Howlett et al. (1999[Howlett, D. R., Perry, A. E., Godfrey, F., Swatton, J. E., Jennings, K. H., Spitzfaden, C., Wadsworth, H., Wood, S. J. & Markwell, R. E. (1999). Biochem. J. 340, 283-289.]); Twyman & Allsop (1999[Twyman, L. J. & Allsop, D. (1999). Tetrahedron Lett. 40, 9383-9384.]).

[Scheme 1]

Experimental

Crystal data
  • C12H11FO3S

  • Mr = 254.27

  • Monoclinic, P 21 /n

  • a = 10.6009 (9) Å

  • b = 8.3319 (7) Å

  • c = 13.395 (1) Å

  • β = 96.138 (1)°

  • V = 1176.34 (17) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.28 mm−1

  • T = 173 K

  • 0.25 × 0.20 × 0.16 mm

Data collection
  • Bruker SMART CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 2000[Sheldrick, G. M. (2000). SADABS. University of Göttingen, Germany.]) Tmin = 0.931, Tmax = 0.958

  • 9646 measured reflections

  • 2543 independent reflections

  • 1541 reflections with I > 2σ(I)

  • Rint = 0.072

Refinement
  • R[F2 > 2σ(F2)] = 0.047

  • wR(F2) = 0.113

  • S = 1.16

  • 2543 reflections

  • 159 parameters

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.28 e Å−3

  • Δρmin = −0.33 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
O2—H2⋯O3i 0.85 (5) 1.81 (5) 2.654 (3) 177 (5)
Symmetry code: (i) -x+2, -y, -z+1.

Data collection: SMART (Bruker, 2001[Bruker (2001). SAINT and SMART. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2001[Bruker (2001). SAINT and SMART. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: ORTEP-3 (Farrugia, 1997[Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565.]) and DIAMOND (Brandenburg, 1998[Brandenburg, K. (1998). DIAMOND. Crystal Impact GbR, Bonn, Germany.]); software used to prepare material for publication: SHELXL97.

Supporting information


Comment top

Molecules involving benzofuran moiety have attracted considerable interest in the view of their pharmacological properties (Howlett et al., 1999; Twyman & Allsop, 1999). As a part of our ongoing studies on the synthesis and structures of 2–(5–halo–1–benzofuran–2–yl) acetic acid analogues, the crystal structures of 2–(5–bromo–3–methylsulfanyl–1–benzofuran–2–yl) acetic acid (Choi et al., 2009a) and 2–(5–fluoro–3–methylsulfanyl–1–benzofuran–2–yl) acetic acid (Choi et al., 2009b) have been described in the literature. Here we report the crystal structure of the title compound (Fig. 1).

The benzofuran unit is essentially planar, with a mean deviation of 0.005 (2) 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 (Table 1 and Fig. 2), which link the molecules into centrosymmetric dimers. These dimers are further packed into stacks along the b axis by aromatic π···π interactions between the furan ring and the benzene ring of adjacent benzofuran ring systems. The Cg1···Cg2ii distance is 3.684 (5) Å (Fig. 2; Cg1 and Cg2 is the centroids of the C1/C2/C7/O1/C8 furan ring and the C2–C7 benzene ring, respectively).

Related literature top

For the crystal structures of similar 2–(5–halo–1–benzofuran–2–yl) acetic acid derivatives, see: Choi et al. (2009a,b). For the pharmacological properties of benzofuran compounds, see: Howlett et al. (1999); Twyman & Allsop (1999).

Experimental top

Ethyl 2–(3–ethylsulfanyl–5–fluoro–1–benzofuran–2–yl) acetate (254 mg, 1.0 mmol) was added to a solution of potassium hydroxide (348 mg, 6.0 mmol) in water (20 ml) and methanol (20 ml), and the mixture was refluxed for 6h, 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 87%, m.p. 401–402 K; Rf = 0.69 (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: EI–MS 254 [M+].

Refinement top

Atom H2 of the hydroxy group was found in a difference Fourier map and refined freely. The other 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, and 0.96 Å for the methyl H atoms with Uiso(H) = 1.2Ueq(C) for the aryl and methylene H atoms, and 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 with the atom numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are presented as small cycles of arbitrary radius.
[Figure 2] Fig. 2. O—H···O and π···π interactions (dotted lines) in the title compound. Cg denotes the ring centroids. [Symmetry codes: (i) - x + 2, - y, - z + 1; (ii) - x + 1, - y + 1, - z + 1; (iii) x + 1, y - 1, z.]
2-(3-Ethylsulfanyl-5-fluoro-1-benzofuran-2-yl)acetic acid top
Crystal data top
C12H11FO3SF(000) = 528
Mr = 254.27Dx = 1.436 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 2478 reflections
a = 10.6009 (9) Åθ = 2.3–27.4°
b = 8.3319 (7) ŵ = 0.28 mm1
c = 13.395 (1) ÅT = 173 K
β = 96.138 (1)°Block, colorless
V = 1176.34 (17) Å30.25 × 0.20 × 0.16 mm
Z = 4
Data collection top
Bruker SMART CCD
diffractometer
2543 independent reflections
Radiation source: fine-focus sealed tube1541 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.072
Detector resolution: 10.0 pixels mm-1θmax = 27.0°, θmin = 2.3°
ϕ and ω scansh = 1313
Absorption correction: multi-scan
(SADABS; Sheldrick, 2000)
k = 1010
Tmin = 0.931, Tmax = 0.958l = 1717
9646 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)] = 0.047Hydrogen site location: difference Fourier map
wR(F2) = 0.113H atoms treated by a mixture of independent and constrained refinement
S = 1.16 w = 1/[σ2(Fo2) + (0.P)2 + 1.581P]
where P = (Fo2 + 2Fc2)/3
2543 reflections(Δ/σ)max < 0.001
159 parametersΔρmax = 0.28 e Å3
0 restraintsΔρmin = 0.33 e Å3
Crystal data top
C12H11FO3SV = 1176.34 (17) Å3
Mr = 254.27Z = 4
Monoclinic, P21/nMo Kα radiation
a = 10.6009 (9) ŵ = 0.28 mm1
b = 8.3319 (7) ÅT = 173 K
c = 13.395 (1) Å0.25 × 0.20 × 0.16 mm
β = 96.138 (1)°
Data collection top
Bruker SMART CCD
diffractometer
2543 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2000)
1541 reflections with I > 2σ(I)
Tmin = 0.931, Tmax = 0.958Rint = 0.072
9646 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0470 restraints
wR(F2) = 0.113H atoms treated by a mixture of independent and constrained refinement
S = 1.16Δρmax = 0.28 e Å3
2543 reflectionsΔρmin = 0.33 e Å3
159 parameters
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
S0.76702 (8)0.59687 (10)0.63171 (7)0.0380 (2)
F0.2776 (2)0.4175 (3)0.75176 (16)0.0561 (6)
O10.5990 (2)0.2294 (2)0.48565 (15)0.0279 (5)
O20.9881 (2)0.1796 (3)0.4247 (2)0.0459 (7)
H21.034 (5)0.097 (6)0.437 (4)0.11 (2)*
O30.8642 (2)0.0735 (3)0.53184 (18)0.0403 (6)
C10.6717 (3)0.4365 (3)0.5848 (2)0.0252 (7)
C20.5483 (3)0.3918 (3)0.6122 (2)0.0247 (7)
C30.4702 (3)0.4454 (4)0.6824 (2)0.0327 (8)
H30.49340.53040.72550.039*
C40.3580 (3)0.3667 (4)0.6845 (3)0.0374 (9)
C50.3184 (3)0.2392 (4)0.6226 (3)0.0387 (9)
H50.24040.19070.62800.046*
C60.3949 (3)0.1847 (4)0.5531 (2)0.0334 (8)
H60.37110.09920.51070.040*
C70.5087 (3)0.2634 (3)0.5496 (2)0.0251 (7)
C80.6966 (3)0.3365 (4)0.5101 (2)0.0263 (7)
C90.8058 (3)0.3237 (4)0.4507 (2)0.0344 (8)
H9A0.85780.41900.46250.041*
H9B0.77420.32190.38010.041*
C100.8882 (3)0.1785 (4)0.4735 (2)0.0290 (7)
C110.8469 (4)0.5118 (4)0.7462 (3)0.0505 (11)
H11A0.88600.59810.78710.061*
H11B0.78400.46180.78360.061*
C120.9460 (4)0.3907 (5)0.7297 (3)0.0584 (12)
H12A0.90690.29890.69590.088*
H12B0.98890.35830.79320.088*
H12C1.00610.43690.68920.088*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
S0.0381 (5)0.0222 (4)0.0500 (5)0.0057 (4)0.0124 (4)0.0003 (4)
F0.0489 (13)0.0634 (15)0.0605 (14)0.0130 (12)0.0265 (11)0.0092 (12)
O10.0296 (12)0.0246 (11)0.0286 (12)0.0014 (10)0.0018 (10)0.0065 (9)
O20.0306 (14)0.0502 (17)0.0602 (17)0.0095 (13)0.0200 (13)0.0200 (14)
O30.0360 (14)0.0379 (14)0.0499 (15)0.0090 (11)0.0177 (12)0.0116 (12)
C10.0288 (17)0.0182 (15)0.0268 (16)0.0005 (13)0.0051 (13)0.0020 (12)
C20.0282 (16)0.0197 (15)0.0245 (16)0.0045 (13)0.0046 (13)0.0024 (13)
C30.041 (2)0.0254 (17)0.0309 (18)0.0074 (15)0.0003 (16)0.0013 (14)
C40.036 (2)0.039 (2)0.040 (2)0.0126 (16)0.0109 (17)0.0143 (16)
C50.0277 (18)0.0320 (19)0.056 (2)0.0019 (15)0.0017 (17)0.0157 (17)
C60.0317 (19)0.0238 (16)0.042 (2)0.0001 (15)0.0079 (16)0.0053 (15)
C70.0270 (17)0.0192 (15)0.0278 (17)0.0021 (13)0.0029 (14)0.0036 (13)
C80.0256 (17)0.0233 (15)0.0294 (17)0.0018 (14)0.0003 (14)0.0020 (13)
C90.0333 (19)0.0324 (18)0.0375 (19)0.0064 (15)0.0047 (16)0.0048 (15)
C100.0265 (18)0.0307 (17)0.0298 (18)0.0012 (15)0.0032 (14)0.0001 (14)
C110.062 (3)0.042 (2)0.042 (2)0.002 (2)0.0234 (19)0.0088 (18)
C120.051 (2)0.059 (3)0.060 (3)0.002 (2)0.017 (2)0.020 (2)
Geometric parameters (Å, º) top
S—C11.751 (3)C5—C61.376 (5)
S—C111.815 (4)C5—H50.9300
F—C41.371 (4)C6—C71.379 (4)
O1—C81.379 (4)C6—H60.9300
O1—C71.380 (4)C8—C91.477 (4)
O2—C101.303 (4)C9—C101.504 (4)
O2—H20.85 (5)C9—H9A0.9700
O3—C101.217 (4)C9—H9B0.9700
C1—C81.349 (4)C11—C121.491 (5)
C1—C21.445 (4)C11—H11A0.9700
C2—C31.391 (4)C11—H11B0.9700
C2—C71.395 (4)C12—H12A0.9600
C3—C41.362 (5)C12—H12B0.9600
C3—H30.9300C12—H12C0.9600
C4—C51.385 (5)
C1—S—C11101.79 (15)C1—C8—O1112.0 (3)
C8—O1—C7105.8 (2)C1—C8—C9132.1 (3)
C10—O2—H2112 (4)O1—C8—C9115.9 (3)
C8—C1—C2106.5 (3)C8—C9—C10114.9 (3)
C8—C1—S125.9 (3)C8—C9—H9A108.6
C2—C1—S127.5 (2)C10—C9—H9A108.6
C3—C2—C7119.4 (3)C8—C9—H9B108.6
C3—C2—C1135.2 (3)C10—C9—H9B108.6
C7—C2—C1105.5 (3)H9A—C9—H9B107.5
C4—C3—C2116.3 (3)O3—C10—O2124.3 (3)
C4—C3—H3121.8O3—C10—C9123.5 (3)
C2—C3—H3121.8O2—C10—C9112.2 (3)
C3—C4—F118.1 (3)C12—C11—S114.3 (3)
C3—C4—C5124.5 (3)C12—C11—H11A108.7
F—C4—C5117.4 (3)S—C11—H11A108.7
C6—C5—C4119.7 (3)C12—C11—H11B108.7
C6—C5—H5120.2S—C11—H11B108.7
C4—C5—H5120.2H11A—C11—H11B107.6
C5—C6—C7116.6 (3)C11—C12—H12A109.5
C5—C6—H6121.7C11—C12—H12B109.5
C7—C6—H6121.7H12A—C12—H12B109.5
C6—C7—O1126.2 (3)C11—C12—H12C109.5
C6—C7—C2123.5 (3)H12A—C12—H12C109.5
O1—C7—C2110.3 (3)H12B—C12—H12C109.5
C11—S—C1—C8101.3 (3)C8—O1—C7—C21.0 (3)
C11—S—C1—C283.6 (3)C3—C2—C7—C60.1 (4)
C8—C1—C2—C3179.5 (3)C1—C2—C7—C6179.3 (3)
S—C1—C2—C34.6 (5)C3—C2—C7—O1179.8 (3)
C8—C1—C2—C70.4 (3)C1—C2—C7—O10.8 (3)
S—C1—C2—C7176.2 (2)C2—C1—C8—O10.2 (3)
C7—C2—C3—C40.2 (4)S—C1—C8—O1175.7 (2)
C1—C2—C3—C4179.3 (3)C2—C1—C8—C9179.1 (3)
C2—C3—C4—F179.1 (3)S—C1—C8—C93.2 (5)
C2—C3—C4—C50.2 (5)C7—O1—C8—C10.7 (3)
C3—C4—C5—C60.0 (5)C7—O1—C8—C9179.8 (2)
F—C4—C5—C6179.3 (3)C1—C8—C9—C10109.0 (4)
C4—C5—C6—C70.2 (5)O1—C8—C9—C1072.1 (4)
C5—C6—C7—O1179.6 (3)C8—C9—C10—O34.1 (5)
C5—C6—C7—C20.3 (4)C8—C9—C10—O2175.1 (3)
C8—O1—C7—C6179.1 (3)C1—S—C11—C1272.7 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H2···O3i0.85 (5)1.81 (5)2.654 (3)177 (5)
Symmetry code: (i) x+2, y, z+1.

Experimental details

Crystal data
Chemical formulaC12H11FO3S
Mr254.27
Crystal system, space groupMonoclinic, P21/n
Temperature (K)173
a, b, c (Å)10.6009 (9), 8.3319 (7), 13.395 (1)
β (°) 96.138 (1)
V3)1176.34 (17)
Z4
Radiation typeMo Kα
µ (mm1)0.28
Crystal size (mm)0.25 × 0.20 × 0.16
Data collection
DiffractometerBruker SMART CCD
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2000)
Tmin, Tmax0.931, 0.958
No. of measured, independent and
observed [I > 2σ(I)] reflections
9646, 2543, 1541
Rint0.072
(sin θ/λ)max1)0.639
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.047, 0.113, 1.16
No. of reflections2543
No. of parameters159
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.28, 0.33

Computer programs: SMART (Bruker, 2001), SAINT (Bruker, 2001), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 1997) and DIAMOND (Brandenburg, 1998), SHELXL97 (Sheldrick, 2008.

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2—H2···O3i0.85 (5)1.81 (5)2.654 (3)177 (5)
Symmetry code: (i) x+2, y, z+1.
 

References

First citationBrandenburg, K. (1998). DIAMOND. Crystal Impact GbR, Bonn, Germany.
First citationBruker (2001). SAINT and SMART. Bruker AXS Inc., Madison, Wisconsin, USA.
First citationChoi, H. D., Seo, P. J., Son, B. W. & Lee, U. (2009a). Acta Cryst. E65, o563.  Web of Science CSD CrossRef IUCr Journals
First citationChoi, H. D., Seo, P. J., Son, B. W. & Lee, U. (2009b). Acta Cryst. E65, o1813.  Web of Science CSD CrossRef IUCr Journals
First citationFarrugia, L. J. (1997). J. Appl. Cryst. 30, 565.  CrossRef IUCr Journals
First citationHowlett, D. R., Perry, A. E., Godfrey, F., Swatton, J. E., Jennings, K. H., Spitzfaden, C., Wadsworth, H., Wood, S. J. & Markwell, R. E. (1999). Biochem. J. 340, 283–289.  Web of Science CrossRef PubMed CAS
First citationSheldrick, G. M. (2000). SADABS. University of Göttingen, Germany.
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals
First citationTwyman, L. J. & Allsop, D. (1999). Tetrahedron Lett. 40, 9383–9384.  Web of Science CrossRef CAS

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