3-(4-Bromophenylsulfonyl)-5-cyclohexyl-2-methyl-1-benzofuran

In the title compound, C21H21BrO3S, the cyclohexyl ring adopts a chair conformation. The 4-bromophenyl ring makes a dihedral angle of 80.88 (6)° with the mean plane of the benzofuran fragment. An intramolecular C—H⋯O hydrogen bond is formed between an O atom of the sulfonyl group and one H atom of the aromatic ring such that a five-membered ring is formed. The crystal packing is stabilized by an intermolecular C—H⋯O hydrogen bond, which links the molecules into chains with graph-set notation C(6) running parallel to the c axis, and π–π stacking interactions [centroid–centroid distance = 3.6129 (12) Å].

In the title compound, C 21 H 21 BrO 3 S, the cyclohexyl ring adopts a chair conformation. The 4-bromophenyl ring makes a dihedral angle of 80.88 (6) with the mean plane of the benzofuran fragment. An intramolecular C-HÁ Á ÁO hydrogen bond is formed between an O atom of the sulfonyl group and one H atom of the aromatic ring such that a five-membered ring is formed. The crystal packing is stabilized by an intermolecular C-HÁ Á ÁO hydrogen bond, which links the molecules into chains with graph-set notation C(6) running parallel to the c axis, andstacking interactions [centroidcentroid distance = 3.6129 (12) Å ].   Table 1 Hydrogen-bond geometry (Å , ). 3-(4-Bromophenylsulfonyl)-5-cyclohexyl-2-methyl-1-benzofuran H. D. Choi, P. J. Seo and U. Lee

Comment
Benzofuran derivatives have drawn much interest in view of their valuable biological properties such as antibacterial and antifungal, antitumor and antiviral, and antimicrobial 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 study of 5-cyclohexyl-2-methyl-1-benzofuran derivatives containing either 3-(4-fluorophenylsulfonyl) (Choi et al., 2011) or 3-phenylsulfonyl (Seo et al., 2011 substituents, we report herein the crystal structure of the title compound. In the title molecule  (6)°. An intramolecular C-H···O hydrogen bond is formed between an O atom of the sulfonyl group and one H atom of the aromatic ring such that a five-membered ring is formed. The crystal packing is stabilized by an intermolecular C-H···O hydrogen bond, which links the molecules into chains with graph-set notation C(6) (Bernstein et al., 1995) running parallel to c axis, Fig.2, Table 1 and π-π stacking interactions, Fig.3 , Table2.
Experimental 77% 3-chloroperoxybenzoic acid (448 mg, 2 mmol) was added in small portions to a stirred solution of 3-(4-bromophenylsulfanyl)-5-cyclohexyl-2-methyl-1-benzofuran (361 mg, 0.9 mmol) in dichloromethane (30 mL) at 273 K. After being stirred at room temperature for 10h, 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 (benzene) to afford the title compound as a colorless solid [yield 67%, m.p. 459-460 K; R f = 0.51 (benzene)]. Single crystals suitable for X-ray diffraction were prepared by slow evaporation of a solution of the title compound in acetone 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 0.98Å 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 the atom numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are presented as 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.