(R)-2-Phenoxy-1-(4-phenyl-2-sulfanylidene-1,3-oxazolidin-3-yl)ethanone

The central 1,3-oxazolidine-2-thione ring in the title compound, C17H15NO3S, is approximately planar with maximum deviations of 0.036 (4) and −0.041 (5) Å for the O and methylene-C atoms, respectively. The dihedral angles formed between this plane and the two benzene rings, which lie to the same side of the central plane, are 86.5 (2) [ring-bound benzene] and 50.6 (3)°. The ethan-1-one residue is also twisted out of the central plane, forming a O—C—N—C torsion angle of 151.5 (5)°. The dihedral angle formed by the benzene rings is 62.8 (2)° so that overall, the molecule has a twisted U-shape. In the crystal, molecules are linked into supramolecular arrays two molecules thick in the bc plane through C—H⋯O, C—H⋯S and C—H⋯π interactions.

The central 1,3-oxazolidine-2-thione ring in the title compound, C 17 H 15 NO 3 S, is approximately planar with maximum deviations of 0.036 (4) and À0.041 (5) Å for the O and methylene-C atoms, respectively. The dihedral angles formed between this plane and the two benzene rings, which lie to the same side of the central plane, are 86.5 (2) [ringbound benzene] and 50.6 (3) . The ethan-1-one residue is also twisted out of the central plane, forming a O-C-N-C torsion angle of 151.5 (5) . The dihedral angle formed by the benzene rings is 62.8 (2) so that overall, the molecule has a twisted U-shape. In the crystal, molecules are linked into supramolecular arrays two molecules thick in the bc plane through C-HÁ Á ÁO, C-HÁ Á ÁS and C-HÁ Á Á interactions.
The molecular structure of (I), Fig. 1, features a planar 1,3-oxazolidine-2-thione ring with the maximum deviations from the least-squares plane being 0.036 (4) for atom O1 and -0.041 (5) for atom C2. With reference to this plane, the two benzene rings are orientated to the same side and form dihedral angles of 86.5 (2) [ring-bound benzene ring] and 50.6 (2)°, respectively, with it. The ethan-1-one group is not co-planar with the five-membered ring as seen in the value of the O2-C10-N-C1 torsion angle of 151.5 (5) °; the carbonyl-O2 atom lies to the opposide side of the central plane to the benzene rings. The dihedral angle formed between the two benzene rings of 62.8 (2) ° indicates a non-parallel alignment.
Overall, the molecule of (I) adopts a twisted U-shape.
The presence of C-H···O and C-H···S contacts, Table 1, leads to the formation of supramolecular 2-D arrays in the bc-plane, Fig. 2. The layers are two molecules thick. Additional stability to the layers is afforded by C-H···π interactions, Table 1. The layers with a flat topology stack along the a-direction, Fig. 3.
After 48 h under stirring, the dicyclohexylurea formed was filtered off and the precipitate washed with methylene chloride (10 ml). The organic layers were washed with a sat. aq. solution of NaHCO 3 (20 ml) and dried over Na 2 SO 4 . Filtration and evaporation of the solvent in vacuum gave the crude product which was purified by flash column chromatography on silica gel with 30% acetone in hexanes to give the pure product as a white solid (320 mg, 37%

Special details
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The 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 > 2σ(F 2 ) is used only for calculating Rfactors(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.