Isopropyl 2-(5-methyl-3-methyl­sulfinyl-1-benzofuran-2-yl)acetate

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

doi:10.1107/S1600536808031796

. 2008 Oct 9;64(Pt 11):o2079. doi: 10.1107/S1600536808031796

Isopropyl 2-(5-methyl-3-methylsulfinyl-1-benzofuran-2-yl)acetate

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

PMCID: PMC2959682 PMID: 21580944

Abstract

The title compound, C₁₅H₁₈O₄S, was prepared by the oxidation of isopropyl 2-(5-methyl-3-methylsulfanyl-1-benzofuran-2-yl)acetate with 3-chloroperoxybenzoic acid. The crystal structure is stabilized by intermolecular π–π interactions between the benzene rings; the centroid–centroid distance between the adjacent benzene rings (symmetry code: Inline graphic ) is 3.713 (2) Å. In addition, C—H⋯π and weak intermolecular C—H⋯O interactions are present in the structure.

Related literature

For the crystal structures of similar 2-(5-methyl-3-methylsulfinyl-1-benzofuran-2-yl)acetic acid derivatives, see: Choi et al. (2007 ▶, 2008 ▶).

Experimental

Crystal data

C₁₅H₁₈O₄S
M _r = 294.35
Triclinic,
a = 8.1829 (5) Å
b = 9.7027 (6) Å
c = 10.6545 (7) Å
α = 73.057 (1)°
β = 77.463 (1)°
γ = 66.421 (1)°
V = 736.76 (8) Å³
Z = 2
Mo Kα radiation
μ = 0.23 mm⁻¹
T = 298 (2) K
0.40 × 0.30 × 0.30 mm

Data collection

Bruker SMART CCD diffractometer
Absorption correction: none
5802 measured reflections
2838 independent reflections
2479 reflections with I > 2σ(I)
R _int = 0.035

Refinement

R[F ² > 2σ(F ²)] = 0.036
wR(F ²) = 0.105
S = 1.07
2838 reflections
185 parameters
H-atom parameters constrained
Δρ_max = 0.22 e Å⁻³
Δρ_min = −0.24 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/S1600536808031796/fb2111sup1.cif

e-64-o2079-sup1.cif^{(18.7KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808031796/fb2111Isup2.hkl

e-64-o2079-Isup2.hkl^{(139.3KB, hkl)}

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

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

Cg1 and Cg2 are the centroids of the C2–C7 and C1/C2/C7/C8/O1 rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C9—H9A⋯O2ⁱ	0.97	2.38	3.249 (2)	149
C13—H13⋯Cg1ⁱⁱ	0.98	2.91	3.656 (2)	134
C15—H15C⋯Cg2ⁱⁱ	0.96	2.96	3.837 (2)	152

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

supplementary crystallographic information

Comment

This work is related to our previous communications on the synthesis and structure of 2-(5-methyl-3-methylsulfinyl-1-benzofuran-2-yl)acetic acid analogues, viz. ethyl 2-(5-methyl-3-methylsulfinyl-1-benzofuran-2-yl)acetate (Choi et al., 2007) and methyl 2-(5-methyl-3-methylsulfinyl-1-benzofuran-2-yl)acetate (Choi et al., 2008). Here we report the crystal structure of the title compound, isopropyl 2-(5-methyl-3-methylsulfinyl-1-benzofuran-2-yl)acetate (Fig. 1).

The benzofuran unit is essentially planar, with a mean deviation of 0.004 (1) Å from the least-squares plane defined by the nine constituent atoms. The molecular packing (Fig. 2) is stabilized by π—π electron interactions between the benzofuran rings of the adjacent molecules. The distances between the centroids of the stacked benzene rings are 3.713 (2) Å (symmetry code: 1-x, 1-y, 1-z). The crystal packing is further stabilized by C—H···π electron interactions (Tab. 1). Additionally, intermolecular C—H···O interactions are present in the structure (Tab. 1).

Experimental

77% 3-chloroperoxybenzoic acid (471 mg, 2.1 mmol) was added in small portions to a stirred solution of isopropyl 2-(5-methyl-3-methylsulfanyl-1-benzofuran-2-yl)acetate (556 mg, 2.0 mmol) in dichloromethane (40 ml) at 273 K. After having been stirred for 3 h at room temperature, the mixture was washed with saturated sodium hydrogencarbonate solution and the organic layer was separated, 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 81%, m.p. 403–404 K; R_f = 0.74 (ethyl acetate)]. Single crystals suitable for X-ray diffraction were prepared by evaporation of a solution of the title compound in ethyl acetate at room temperature. The average crystal size was approximately 1.0 x 1.0 x 0.5 mm. The crystals are colourless and soluble in polar solvents. Spectroscopic analysis: ¹H NMR (CDCl₃, 400 MHz) δ 1.25 (d, J = 6.20 Hz, 6H), 2.46 (s, 3H), 3.08 (s, 3H), 3.99 (s, 2H), 5.00–5.08 (m, 1H), 7.17 (d, J = 8.44 Hz, 1H), 7.39 (d, J = 8.44 Hz, 1H), 7.74 (s, 1H); EI—MS 294 [M⁺].