Crystal structure of 2-methoxy-2-[(4-methylphenyl)sulfanyl]-1-phenylethan-1-one

In the title β-thiocarbonyl compound, C16H16O2S, the carbonyl and methoxy O atoms are approximately coplanar [O—C—C—O torsion angle = −18.2 (5)°] and syn to each other, and the tolyl ring is orientated to lie over them. The dihedral angle between the planes of the two rings is 44.03 (16)°. In the crystal, supramolecular chains are formed along the c axis mediated by C—H⋯O interactions involving methine and methyl H atoms as donors, with the carbonyl O atom accepting both bonds; these pack with no specific intermolecular interactions between them.

After 30 minutes, a solution of 4-methylphenyl disulfide (0.748 g, 3.04 mmol) with hexamethylphosphoramide (HMPA) (0.5 ml, 2.76 mmol) dissolved in THF (10 ml) was added drop wise to the enolate solution (Zoretic & Soja, 1976). After stirring for 3 h, water (50 ml) was added at room temperature and extraction with diethyl ether was performed. The organic layer was then treated with a saturated solution of ammonium chloride until neutral pH and dried over anhydrous magnesium sulfate. A brown oil was obtained after evaporation of the solvent. Purification through flash chromatography with n-hexane was used to remove the non-polar reactant (disulfide) then acetone to give a mixture of both acetophenones (product and reactant). Crystallization was performed by vapour diffusion of n-hexane into a chloroform solution held at 283 K to give pure product (0.3 g, yield = 40%

S2.2. Refinement
Carbon-bound H-atoms were placed in calculated positions (C-H = 0.93 to 0.98 Å) and were included in the refinement in the riding model approximation, with U iso (H) = 1.2-1.5U eq (C).

Figure 1
The molecular structure of the title compound showing the atom-labelling scheme and displacement ellipsoids at the 35% probability level.

Figure 2
A view of the supramolecular chain along the c axis mediated by C-H···O interactions (bluee dashed lines).

Figure 3
A view in projection down the c axis of the unit-cell contents. The C-H···O interactions are shown as blue dashed lines.