2-Methyl-1-(3-methylphenylsulfonyl)naphtho[2,1-b]furan

In the title compound, C20H16O3S, the dihedral angle between the mean planes of the naphthofuran and 3-methylphenyl fragments is 88.56 (2)°. In the crystal, molecules are linked via pairs of C—H⋯O hydrogen bonds, forming inversion dimers. These dimers are linked by π–π interactions between the furan rings of neighbouring molecules [centroid–centroid distance = 3.701 (2) Å] into supramolecular chains running along the a-axis direction.

In the title compound, C 20 H 16 O 3 S, the dihedral angle between the mean planes of the naphthofuran and 3-methylphenyl fragments is 88.56 (2) . In the crystal, molecules are linked via pairs of C-HÁ Á ÁO hydrogen bonds, forming inversion dimers. These dimers are linked byinteractions between the furan rings of neighbouring molecules [centroid-centroid distance = 3.701 (2) Å ] into supramolecular chains running along the a-axis direction.

Related literature
For background information and the crystal structures of related compounds, see: Choi et al. (2008Choi et al. ( , 2012a Table 1 Hydrogen-bond geometry (Å , ).
Supporting information for this paper is available from the IUCr electronic archives (Reference: ZQ2218).
In the title molecule ( Fig. 1), the naphthofuran unit is essentially planar, with a mean deviation of 0.025 (1) Å from the least-squares plane defined by the thirteen constituent atoms. The 3-methylphenyl ring is essentially planar, with a mean deviation of 0.014 (1) Å from the least-squares plane defined by the six constituent atoms. The dihedral angle formed by the naphthofuran ring system and the 3-methylphenyl ring is 88.56 (2)°. In the crystal structure ( Fig. 2), molecules are connected via pairs of C-H···O hydrogen bonds (Table 1), forming inversion dimers. These dimers are further packed by π-π interactions between the furan rings of neighbouring molecules, with a Cg1···Cg1 ii distance of 3.701 (2) Å and an interplanar distance of 3.503 (2) Å resulting in a slippage of 1.194 (2) Å (Cg1 is the centroid of the C1/C2/C11/O1/C12 furan ring), forming supramolecular chains running along the a-axis direction.

Experimental
3-Chloroperoxybenzoic acid (77%, 538 mg, 2.4 mmol) was added in small portions to a stirred solution of 2-methyl-1-(3methylphenylsulfanyl)naphtho[2,1-b]furan (334 mg, 1.1 mmol) in dichloromethane (40 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 (hexane-ethyl acetate, 4:1 v/v) to afford the title compound as a colorless solid [yield 72%, m.p. 424-425 K; R f = 0.52 (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 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 and 0.95 Å 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 using the SHELXL-97's command AFIX 137 (Sheldrick, 2008  The molecular structure of the title molecule with the atom numbering scheme. The displacement ellipsoids are drawn at the 50% probability level. The hydrogen atoms are presented as small spheres of arbitrary radius.

2-Methyl-1-(3-methylphenylsulfonyl)naphtho[2,1-b]furan
Crystal data  where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.003 Δρ max = 0.31 e Å −3 Δρ min = −0.52 e Å −3 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.