5-Bromo-3-cyclohexylsulfinyl-2-methyl-1-benzofuran

In the asymmetric unit of the title compound, C15H17BrO3S, there are two independent molecules. The cyclohexane rings in each adopt classic chair conformations. In the crystal, molecules are linked by weak intermolecular C—H⋯O hydrogen bonds and aromatic π–π interactions between the furan rings of symmetry-related molecules [centroid–centroid distance = 3.555 (2) Å].

In the asymmetric unit of the title compound, C 15 H 17 BrO 3 S, there are two independent molecules. The cyclohexane rings in each adopt classic chair conformations. In the crystal, molecules are linked by weak intermolecular C-HÁ Á ÁO hydrogen bonds and aromaticinteractions between the furan rings of symmetry-related molecules [centroid-centroid distance = 3.555 (2) Å ].
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: LH5201).

Comment
Many compounds involving a benzofuran ring have potential pharmacological properties such as antifungal, antitumor and antiviral, and antimicrobial activities (Aslam et al., 2006;Galal et al., 2009, Khan et al., 2005. These compounds occur in a wide range of natural products (Akgul & Anil, 2003;Soekamto et al., 2003). As a part of our ongoing study of the substituent effect on the solid state structures of 5-bromo-2-methyl-3-methylsufinyl-1-benzofuran analogues (Choi et al., 2007, Seo et al., 2009, we report herein the crystal structure of the title compound. The asymmetric unit of the title compound is shown in Fig. 1. There are two independent molecules [A and B] in which the benzofuran unit is essentially planar in each with a mean deviation of 0.013 (2) Å and 0.014 (2) Å for A and B, respectively from the least-squares plane defined by the nine constituent atoms. The cyclohexyl rings are in the chair form. The molecular packing ( Fig. 2) is stabilized by weak intermolecular C-H···O hydrogen bonds; the first one between a benzene H atom and the oxygen atom of the S═O unit (Table 1; C5-H5···O2 i ), and the second one between a cyclohexyl H atom and the oxygen atom of the S═O unit (Table 1; C25-H25···O2). An intramolecular hydrogen bond exists between a cyclohexyl H atom and the oxygen atom of the S═O unit (Table 1; C25-H25···O2). Further stabilization is provided by aromatic π-π interactions between the furan rings of symmetry related molecules, with a Cg1···Cg2(1-x,1/2+y,3/2-z) distance of 3.555 (2) Å (Cg1 and Cg2 are the centroids of the C1/C2/C7/O1/C8 and C16/C17/C22/O3/C23 furan rings, respectively).

Experimental
77% 3-chloroperoxybenzoic acid (224 mg, 1.0 mmol) was added in small portions to a stirred solution of 5-bromo-3-cyclohexylsulfanyl-2-methyl-1-benzofuran (293 mg, 0.9 mmol) in dichloromethane (40 mL) at 273 K. After being stirred at room temperature for 3h, 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, 2:1 v/v) to afford the title compound as a colorless solid [yield 72%, m.p. 388-389 K; R f = 0.45 (hexane-ethyl acetate, 2:1 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.

Refinement
All H atoms were positioned geometrically and refined using a riding model, with C-H = 0.95 Å for aryl, 1.00 Å for methine, 0.99 Å for methylene, and 0.98 Å for methyl H atoms, respectively. U iso (H) =1.2U eq (C) for aryl, methine and methylene, and 1.5U eq (C) for methyl H atoms.
supplementary materials sup-2 Figures Fig. 1. The molecular structure of the title compound with displacement ellipsoids drawn at the 50% probability level. H atoms are presented as a small spheres of arbitrary radius.

Special details
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 F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2sigma(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 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 (Å 2 )
x y z U iso */U eq