3-(4-Fluorophenylsulfonyl)-5-isopropyl-2-methyl-1-benzofuran

In the title compound, C18H17FO3S, the 4-fluorophenyl ring makes a dihedral angle of 82.12 (4)° with the plane of the benzofuran fragment. In the crystal structure, molecules are linked by weak intermolecular C—H⋯O hydrogen bonds and C—H⋯π interactions.

In the title compound, C 18 H 17 FO 3 S, the 4-fluorophenyl ring makes a dihedral angle of 82.12 (4) with the plane of the benzofuran fragment. In the crystal structure, molecules are linked by weak intermolecular C-HÁ Á ÁO hydrogen bonds and C-HÁ Á Á interactions.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: XU2750).

Comment
The compounds containing benzofuran ring show potent biological activities such as antifungal (Aslam et al., 2006), antitumor and antiviral (Galal et al., 2009), antimicrobial (Khan et al., 2005) properties. These compounds occur widely in nature (Akgul & Anil, 2003;Soekamto et al., 2003). As a part of our ongoing studies of the effect of side chain substituents on the solid state structures of 2-methyl-3-phenylsulfonyl-1-benzofuran analogues (Choi et al., 2008a,b), we report the crystal structure of the title compound (Fig. 1).
The benzofuran unit is essentially planar, with a mean deviation of 0.113 (1) Å from the least-squares plane defined by the nine constituent atoms. The 4-fluorophenyl ring makes a dihedral angle of 82.12 (4)° with the plane of the benzofuran fragment. The molecular packing ( Fig. 2) is stabilized by an intermolecular C-H···O hydrogen bond between the 4-fluorophenyl H atom and the oxygen of the sulfonyl group, with a C14-H14···O2 i ( Table 1). The crystal packing ( Fig. 3) is further stabilized by three intermolecular C-H···π interactions; the first one between the methyl H atom of the isopropyl group and the furan ring of an adjacent molecule, with a C10-H10B···Cg1 ii , the second one between the methyl H atom of the isopropyl group and the benzene ring of a neighbouring molecule, with a C11-H11B···Cg2 ii , and the third one between the 4-fluorophenyl H atom and the benzene ring of an adjacent benzofuran system, with a C17-H17···Cg2 iii , respectively (Table 1; Cg1 and Cg2 are the centroids of the C1/C2/C7/O3/C8 furan ring and the C2-C7 benzene ring, respectively).

Experimental
77% 3-Chloroperoxybenzoic acid (448 mg, 2.0 mmol) was added in small portions to a stirred solution of 3-(4-fluorophenylsulfanyl)-5-isoproyl-2-methyl-1-benzofuran (270 mg, 0.9 mmol) in dichloromethane (40 mL) at 273 K. After being stirred at room temperature for 8 h, 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 (silica gel, hexane-ethyl acetate, 2:1 v/v) to afford the title compound as a colorless solid [yield 79%, m.p. 402-403 K; Rf = 0.69 (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 benzene 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 and 0.98 Å for methyl H atoms, respectively. U iso (H) = 1.2U eq (C) for aryl and methine, and 1.5U eq (C) for methyl H atoms.

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 S 0.54221 (