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

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

doi:10.1107/S160053680900453X

. 2009 Feb 13;65(Pt 3):o520. doi: 10.1107/S160053680900453X

Propyl 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: PMC2968554 PMID: 21582183

Abstract

In the title compound, C₁₄H₁₅BrO₄S, the S atom has a distorted trigonal–pyramidal coordination. The O atom and the methyl group of the methylsulfinyl substituent lie on opposite sides of the plane of the benzofuran fragment. The molecules form slightly slipped π-stacked inversion-symmetric dimers by intermolecular aromatic π–π interactions, with a centroid-to-centroid distance of 3.695 (4) Å between the benzene rings of neighbouring molecules. The crystal packing is further stabilized by intermolecular C—H⋯π interactions between the methylene H atoms of the propyl group towards the benzene and furan rings of neighbouring molecules, respectively. Additionally, the crystal structure exhibits weak intermolecular 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. (2008a ▶,b ▶).

Experimental

Crystal data

C₁₄H₁₅BrO₄S
M _r = 359.23
Triclinic,
a = 8.4538 (6) Å
b = 9.8823 (7) Å
c = 10.3231 (7) Å
α = 72.358 (1)°
β = 81.200 (1)°
γ = 65.443 (1)°
V = 747.16 (9) Å³
Z = 2
Mo Kα radiation
μ = 2.90 mm⁻¹
T = 298 K
0.60 × 0.50 × 0.20 mm

Data collection

Bruker SMART CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1999 ▶) T _min = 0.187, T _max = 0.556
3932 measured reflections
2593 independent reflections
2359 reflections with I > 2σ(I)
R _int = 0.014

Refinement

R[F ² > 2σ(F ²)] = 0.034
wR(F ²) = 0.097
S = 1.07
2593 reflections
182 parameters
H-atom parameters constrained
Δρ_max = 0.62 e Å⁻³
Δρ_min = −0.38 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 global, I. DOI: 10.1107/S160053680900453X/zl2167sup1.cif

e-65-0o520-sup1.cif^{(18.2KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S160053680900453X/zl2167Isup2.hkl

e-65-0o520-Isup2.hkl^{(127.3KB, 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
C11—H11B⋯Cg1ⁱ	0.97	3.02	3.720 (3)	130
C12—H12B⋯Cg2ⁱ	0.97	2.90	3.826 (3)	161
C3—H3⋯O4ⁱⁱ	0.93	2.54	3.424 (3)	159
C5—H5⋯O3ⁱⁱⁱ	0.93	2.58	3.430 (4)	152
C9—H9B⋯O4^iv	0.97	2.37	3.321 (3)	167

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) . Cg1 and Cg2 are the centroids of the C2–C7 benzene ring and the C1/C2/C7/O1/C8 furan ring, respectively.

supplementary crystallographic information

Comment

As a part of our ongoing research on the synthesis and structure of alkyl 2-(5-bromo-3-methylsulfinyl-1-benzofuran-2-yl)acetate analogues, we have recently described the crystal structures of isopropyl 2-(5-bromo-3-methylsulfinyl-1-benzofuran-2-yl)acetate (Choi et al., 2008a) and methyl 2-(5-bromo-3-methylsulfinyl-1-benzofuran-2-yl)acetate (Choi et al., 2008b). Here we report the crystal structure of the title compound, propyl 2-(5-bromo-3-methylsulfinyl-1-benzofuran-2-yl)acetate (Fig. 1).

The benzofuran unit is essentially planar, with a mean deviation of 0.013 (2) Å from the least-squares plane defined by the nine constituent atoms. The molecular packing (Fig. 2) is stabilized by intermolecular π–π stacking interactions between the benzene rings of neighbouring molecules. Via this interaction the molecules form slightly slipped π-stacked inversion symmetric dimers, with a centroid–centroid distance Cg1···Cg1ⁱⁱⁱ of 3.695 (4) Å between the benzene rings of neighbouring molecules. (Cg is the centroid of the C2–C7 benzene ring, symmetry code as in Fig. 2). The molecular packing is further stabilized by C—H···π interactions; one between the hydrogen of the C11-methylene group and the benzene ring of the benzofuran unit, with a C11—H11B···Cg1ⁱ separation of 3.02 Å, and a second between the hydrogen of the C12-methylene group and the furan ring of the benzofuran unit, with a C12—H12B···Cg2ⁱ separation of 2.90 Å (Table 1 and Fig. 2; Cg1 and Cg2 are the centroids of the C2–C7 benzene ring and the C1/C2/C7/O1/C8 furan ring, respectively, symmetry code as in Fig. 2). In addition, three weak intermolecular C—H···O hydrogen bonds in the structure were observed (Table 1 and Fig. 3); one between the hydrogen on benzene ring and the oxygen of the S═O unit (C3—H3···O4ⁱⁱ), a second between the hydrogen on benzene ring and the oxygen of the C═O unit (C5—H5···O3ⁱⁱⁱ), and a third between the hydrogen of the C9–methylene group and the S═O unit (C9—H9B···O4^iv), respectively.

Experimental

77% 3-chloroperoxybenzoic acid (179 mg, 0.8 mmol) was added in small portions to a stirred solution of propyl 2-(5-bromo-3-methylsulfanyl-1-benzofuran-2-yl)acetate (629 mg, 0.75 mmol) in dichloromethane (30 ml) at 273 K. After being stirred for 3 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 81%, m.p. 413–413.5 K; R_f = 0.55 (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 benzene at room temperature. Spectroscopic analysis: ¹H NMR (CDCl₃, 400 MHz) δ 0.94 (t, J = 7.32 Hz, 3H), 1.63–1.72 (m, 2H), 3.07 (s, 3H), 4.05 (s, 2H), 4.11 (t, J = 6.96 Hz, 2H), 7.40 (d, J = 8.76 Hz, 1H), 7.48 (dd, J = 8.76 Hz and J = 1.84 Hz, 1H), 8.09 (d, J = 1.84 Hz, 1H); EI-MS 360 [M+2], 358 [M⁺].