3-Cyclo­pentyl­sulfonyl-5-fluoro-2-methyl-1-benzofuran

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

doi:10.1107/S1600536811021222

. 2011 Jun 18;67(Pt 7):o1689. doi: 10.1107/S1600536811021222

3-Cyclopentylsulfonyl-5-fluoro-2-methyl-1-benzofuran

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

PMCID: PMC3152135 PMID: 21837086

Abstract

There are two independent molecules, A and B, in the asymmetric unit of the title compound, C₁₄H₁₅FO₃S, in each of which the cyclopentyl ring adopts an envelope conformation. The benzofuran units in each molecule are essentially planar, with mean deviations from the least-squares plane defined by the nine constituent ring atoms of 0.009 (2) Å for molecule A and 0.013 (2) Å for molecule B. In the crystal, molecules are linked by weak C—H⋯O hydrogen bonds. In the cyclopentyl ring of molecule B, one C atom is disordered over two positions with site-occupancy factors of 0.60 (2) and 0.40 (2).

Related literature

For the pharmacological activity of benzofuran compounds, see: Aslam et al. (2009 ▶); Galal et al. (2009 ▶); Khan et al. (2005 ▶). For natural products with benzofuran rings, see: Akgul & Anil (2003 ▶); Soekamto et al. (2003 ▶). For a structural study of the related compound 5-bromo-3-cyclopentylsulfinyl-2-methyl-1-benzofuran, see: Seo et al. (2011 ▶).

Experimental

Crystal data

C₁₄H₁₅FO₃S
M _r = 282.32
Triclinic,
a = 10.0568 (8) Å
b = 10.2697 (8) Å
c = 13.2894 (10) Å
α = 95.033 (4)°
β = 109.140 (4)°
γ = 91.229 (4)°
V = 1289.82 (17) Å³
Z = 4
Mo Kα radiation
μ = 0.26 mm⁻¹
T = 173 K
0.26 × 0.24 × 0.20 mm

Data collection

Bruker SMART APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.936, T _max = 0.948
21777 measured reflections
5565 independent reflections
4022 reflections with I > 2σ(I)
R _int = 0.042

Refinement

R[F ² > 2σ(F ²)] = 0.045
wR(F ²) = 0.119
S = 1.03
5565 reflections
361 parameters
20 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.50 e Å⁻³
Δρ_min = −0.31 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); 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 datablock(s) global, I. DOI: 10.1107/S1600536811021222/go2016sup1.cif

e-67-o1689-sup1.cif^{(28.3KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811021222/go2016Isup2.hkl

e-67-o1689-Isup2.hkl^{(272.4KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811021222/go2016Isup3.cml

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
C9—H9C⋯O6ⁱ	0.98	2.45	3.348 (3)	152
C19—H19⋯O6ⁱⁱ	0.95	2.58	3.469 (3)	157
C23—H23A⋯O2ⁱⁱⁱ	0.98	2.50	3.318 (3)	141

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

supplementary crystallographic information

Comment

Many compounds having a benzofuran moiety have attracted much attention due to their valuable biological properties such as antifungal, antimicrobial, antitumor and antiviral activities (Aslam et al., 2009; Galal et al., 2009; Khan et al., 2005). These benzofuran derivatives occur in a wide range of natural products (Akgul & Anil, 2003; Soekamto et al., 2003). As a part of our ongoing studies of the substituent effect on the solid state structures of 3-cyclopentylsulfinyl-5-halo-2-methyl-1-benzofuran analogues (Seo et al., 2011), we report herein on the crystal structure of the title compound.

The asymmetric unit of the title compound is shown in Fig. 1. There are two independent unique molecules [labelled A & B] in which the benzofuran unit is essentially planar, with a mean deviation of 0.009 (2) Å for A and 0.013 (2) Å for B, respectively, from the least-squares plane defined by the nine constituent atoms. The cyclopentyl rings of both molecules are in an envelope form. In the cyclopentyl ring of molecule B, C27 atom is disordered over two positions with site-occupancy factors, from refinement of 0.60 (2) (part 1) and 0.40 (8) (part 2). In the crystal packing (Fig. 2), molecules are linked by weak non-classical intermolecular C–H···O hydrogen bonds; the first one between a methyl H atom and the O atom of the sulfonyl group (Table 1; C9–H9C···O6ⁱ), the second one between a benzene H atom and the O atom of the sulfonyl group (Table 1; C19–H19···O6ⁱⁱ), and the third one between a methyl H atom and the O atom of the sulfonyl group (Table 1; C23–H23A···O2ⁱⁱⁱ).

Experimental

3-chloroperoxybenzoic acid (77%, 560 mg, 2.5 mmol) was added in small portions to a stirred solution of 3-cyclopentylsulfanyl-5-fluoro-2-methyl-1-benzofuran (325 mg, 1.2 mmol) in dichloromethane (40 mL) at 273 K. After being stirred at room temperature for 8h, the mixture was washed with saturated sodium bicarbonate solution and the organic layer was separated, dried over magnesium sulfate, filtered and concentrated at reduced pressure. The residue was purified by column chromatography (hexane-ethyl acetate, 4:1 v/v) to afford the title compound as a colorless solid [yield 71%, m.p. 394-395 K; R_f = 0.49 (hexane-ethyl acetate, 4:1 v/v)]. Single crystals suitable for X-ray diffraction were prepared by slow evaporation of a solution of the title compound in ethyl acetate at room temperature.