3-(4-Fluorophenylsulfonyl)-5-iodo-2,7-dimethyl-1-benzofuran

In the title compound, C16H12FIO3S, the 4-fluorophenyl ring makes a dihedral angle of 72.31 (6)° with the mean plane of the benzofuran fragment. In the crystal, molecules are linked by weak C—H⋯O hydrogen bonds, and by an I⋯I contact [3.7764 (3) Å]. The crystal structure also exhibits a weak C—I⋯π [3.901 (3) Å] interaction and a slipped π–π interaction between the furan and benzene rings of neighbouring molecules [centroid–centroid distance = 3.845 (3), interplanar distance = 3.555 (3) and slippage = 1.465 (3) Å].

In the title compound, C 16 H 12 FIO 3 S, the 4-fluorophenyl ring makes a dihedral angle of 72.31 (6) with the mean plane of the benzofuran fragment. In the crystal, molecules are linked by weak C-HÁ Á ÁO hydrogen bonds, and by an IÁ Á ÁI contact

Comment
Recently, benzofuran derivatives have drawn much attention due to their valuable pharmacological 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 benzofuran derivatives containing either 3-phenylsulfonyl (Choi et al., 2008) or 3-(4-fluorophenylsulfinyl) (Choi et al., 2011) substituents, we report herein the crystal structure of the title compound.
In the title molecule ( Fig. 1), the benzofuran unit is essentially planar, with a mean deviation of 0.007 (2) Å from the least-squares plane defined by the nine constituent atoms. The dihedral angle formed by the 4-fluorophenyl ring and the mean plane of the benzofurn fragment is 72.31 (6)°. The crystal packing (Fig. 2) is stabilized by weak intermolecular C-H···O hydrogen bonds (see Table 1), and by an I···I contact at 3.7764 (3) Å. The crystal packing ( Fig. 3) is further stabilized by a weak C-I···π interaction between the iodine and the benzene ring of an adjacent molecule, with a C4-I1···Cg2 v [3.901 (3) Å] (Cg2 is the centroid of the C2···C7 benzene ring). The crystal packing (Fig. 3) is also exhibits a weak slipped π-π interaction between the furan and benzene rings of adjacent molecules, with a Cg1···Cg2 iv distance of 3.845 (3) Å and an interplanar distance of 3.555 (3) Å resulting in a slippage of 1.465 (3) Å (Cg1 is the centroid of the C1/C2/C7/O1/C8 furan ring).

Experimental
77% 3-chloroperoxybenzoic acid (381 mg, 1.7 mmol) was added in small portions to a stirred solution of 3-(4-fluorophenylsulfanyl)-5-iodo-2,7-dimethyl-1-benzofuran (318 mg, 0.8 mmol) in dichloromethane (30 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 (hexane-ethyl acetate, 4:1 v/v) to afford the title compound as a colorless solid [yield 71%, m.p. 430-431 K; R f = 0.53 (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.

Refinement
All H atoms were positioned geometrically and refined using a riding model, with C-H = 0.95 Å fo the aryl and 0.98 Å for the methylene H atoms. U iso (H) =1.2U eq (C) for the aryl and 1.5U eq (C) for the methyl H atoms.