7-Bromo-2-(4-methylphenyl)-1-(methylsulfinyl)naphtho[2,1-b]furan

In the title compound, C20H15BrO2S, the dihedral angle between the mean plane [r.m.s. deviation = 0.030 (2) Å] of the naphthofuran ring system and the 4-methylphenyl ring is 38.49 (9)°. In the crystal, molecules are linked by C—H⋯π and C—Br⋯π [3.871 (2) Å] interactions into stacks along the b-axis direction. These stacks are further linked by weak C—H⋯O hydrogen bonds, forming a three-dimensional network.

In the title compound, C 20 H 15 BrO 2 S, the dihedral angle between the mean plane [r.m.s. deviation = 0.030 (2) Å ] of the naphthofuran ring system and the 4-methylphenyl ring is 38.49 (9) . In the crystal, molecules are linked by C-HÁ Á Á and C-BrÁ Á Á [3.871 (2) Å ] interactions into stacks along the b-axis direction. These stacks are further linked by weak C-HÁ Á ÁO hydrogen bonds, forming a three-dimensional network.

Related literature
For background information and the crystal structures of related compounds, see: Choi et al. (2009Choi et al. ( , 2010 Table 1 Hydrogen-bond geometry (Å , ).
In the title molecule ( Fig. 1), the naphthofuran unit is essentially planar, with a mean deviation of 0.030 (2) Å from the least-squares plane defined by the thirteen constituent atoms. The dihedral angle between the mean plane of the naphthofuran ring system and the 4-methylphenyl ring is 38.49 (9)°. In the crystal structure ( Fig. 2), molecules are connected by C-H···π (Table 1), and C6-Br1···π [3.871 (2) Å] interactions between the bromine atom and the central benzene ring of a neighbouring molecule with a Br1···Cg1 iii being 3.871 (2) Å (Cg1 is the centroid of the C2/C3/C8/C9/C10/C11 benzene ring), into stacks along the b-axis direction. These stacks are further packed by weak C-H···O hydrogen bonds (Table 1), forming a three-dimensional network.

Experimental
3-Chloroperoxybenzoic acid (77%, 202 mg, 0.9 mmol) was added in small portions to a stirred solution of 7-bromo-2-(4methylphenyl)-1-(methylsulfanyl)naphtho[2,1-b]furan (306 mg, 0.8 mmol) in dichloromethane (40 mL) at 273 K. After being stirred at room temperature for 6h, 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 61%, m.p. 485-486 K; R f = 0.46 (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 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 and 0.98Å for methyl H atoms. U iso (H) = 1.2U eq (C) for aryl and 1.5U eq (C) for methyl H atoms. The positions of methyl hydrogens were optimized rotationally. The highest peak in the difference map is 1.38 Å from S1 and the largest hole is 0.70 Å from Br1. program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 2012) and DIAMOND (Brandenburg, 1998); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).  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.