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

Hong Dae Choi; Pil Ja Seo; Byeng Wha Son; Uk Lee

doi:10.1107/S1600536809020613

. 2009 Jun 6;65(Pt 7):o1498. doi: 10.1107/S1600536809020613

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

Hong Dae Choi ^a, Pil Ja Seo ^a, Byeng Wha Son ^b, Uk Lee ^b,^*

PMCID: PMC2969326 PMID: 21582797

Abstract

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 π–π interactions between the benzene rings of adjacent molecules [centroid–centroid distance = 3.643 (2) Å] and nonclassical C—H⋯O hydrogen bonds.

Related literature

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

Crystal data

C₁₆H₁₉BrO₄S
M _r = 387.28
Triclinic,
a = 8.3704 (4) Å
b = 10.2956 (6) Å
c = 10.524 (1) Å
α = 99.977 (1)°
β = 105.230 (1)°
γ = 100.681 (1)°
V = 836.04 (10) Å³
Z = 2
Mo Kα radiation
μ = 2.60 mm⁻¹
T = 173 K
0.60 × 0.40 × 0.10 mm

Data collection

Bruker SMART CCD diffractometer
Absorption correction: multi-scan SADABS (Sheldrick, 1999 ▶) T _min = 0.302, T _max = 0.769
7179 measured reflections
3579 independent reflections
3304 reflections with I > 2σ(I)
R _int = 0.024

Refinement

R[F ² > 2σ(F ²)] = 0.027
wR(F ²) = 0.072
S = 1.04
3579 reflections
202 parameters
H-atom parameters constrained
Δρ_max = 0.35 e Å⁻³
Δρ_min = −0.59 e Å⁻³

Data collection: SMART (Bruker, 2001 ▶); cell refinement: SAINT (Bruker, 2001 ▶); data reduction: SAINT; 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.

Supplementary Material

Crystal structure: contains datablocks I. DOI: 10.1107/S1600536809020613/cv2569sup1.cif

e-65-o1498-sup1.cif^{(19.3KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809020613/cv2569Isup2.hkl

e-65-o1498-Isup2.hkl^{(175.5KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C3—H3⋯O4ⁱ	0.93	2.56	3.437 (2)	157
C5—H5⋯O3ⁱⁱ	0.93	2.51	3.383 (2)	157
C9—H9A⋯O4ⁱⁱⁱ	0.97	2.26	3.192 (2)	162
C9—H9B⋯O1^iv	0.97	2.61	3.541 (2)	160

Open in a new tab

Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) .

supplementary crystallographic information

Comment

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).

Experimental

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⁺].