5-Chloro-3-ethylsulfinyl-2-(4-iodophenyl)-7-methyl-1-benzofuran

In the title compound, C17H14ClIO2S, the 4-iodophenyl ring makes a dihedral angle of 1.61 (9)° with the benzofuran ring system. In the crystal, molecules are linked through a weak intermolecular C—H⋯O hydrogen bond and an I⋯O contact [3.416 (2) Å]. The ethyl group is disordered over two orientations with site-occupancy factors of 0.402 (7) and 0.598 (7).

In the title compound, C 17 H 14 ClIO 2 S, the 4-iodophenyl ring makes a dihedral angle of 1.61 (9) with the benzofuran ring system. In the crystal, molecules are linked through a weak intermolecular C-HÁ Á ÁO hydrogen bond and an IÁ Á ÁO contact [3.416 (2) Å ]. The ethyl group is disordered over two orientations with site-occupancy factors of 0.402 (7) and 0.598 (7).
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 ethyl group is disordered over two positions with site-occupancy factors of 0.402 (7) (for atom labelled A) and 0.598 (7) (for atom labelled B) in Fig. 1. The dihedral angle formed by the benzofuran plane and the 4-iodophenyl ring is 1.61 (9)°. The molecular packing (Fig. 2) is stabilized by a weak intermolecular C-H···O hydrogen bond between the methylene H atom of the ethyl group and the oxygen of the S═O unit, with a C16A-H16B···O2 i ( Table   1). The crystal packing (Fig. 2) is further stabilized by an I···O halogen-bonding between the iodine and the oxygen of the S═O unit [I···O2 ii = 3.416 (2) Å; C12-I···O2 ii = 161.46 (7)°] (Politzer et al., 2007).

Experimental
77% 3-chloroperoxybenzoic acid (157 mg, 0.7 mmol) was added in small portions to a stirred solution of 5-chloro-3-ethylsulfanyl-2-(4-iodophenyl)-7-methyl-1-benzofuran (300 mg, 0.7 mmol) in dichloromethane (40 mL) at 273 K. After being stirred at room temperature for 5h, 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, 1:1 v/v) to afford the title compound as a colorless solid [yield 76%, m.p. 457-458 K; R/ f = 0.64 (hexane-ethyl acetate, 1:1 v/v)]. 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 = 0.93 Å for aryl, 0.97 Å for methylene, and 0.96 Å for methyl H atoms, and with U iso (H) =1.2U eq (C) for aryl and methylene H atoms, and 1.5U eq (C) for methyl H atoms. The ethyl group was found to be disordered over two positions and modelled with site-occupancy factors, from refinement of 0.402 (7) (part A) and 0.598 (7) (part B), respectively. The displacement ellipsoids of part B were restrained using command ISOR (0.01), sets of C atoms were restrained using command DELU and the distances of C-C were restrained to 1.480 (2) Å using command DFIX. The distances of C-S and C-C were restrained to 0.001Å using command SADI.  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 a small spheres of arbitrary radius. The ethyl group is disordered over two positions with site-occupancy factors, from refinement of 0.402 (7) and 0.598 (7).

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.