(4S)-4-[(R)-Chloro(4-nitrophenyl)methyl]-1,3-oxazolidin-2-one

In the title compound, C10H9ClN2O4, the oxazolidinone ring adopts a near-planar conformation, with mean and maximum deviations of 0.0204 (8) and 0.0328 (8) Å, respectively. The nitro group is twisted slightly from the plane of the benzene ring, making a dihedral angle of 6.79 (3)°. The dihedral angle between the mean oxazolidinone plane and the benzene ring is 56.21 (3)°. In the crystal, N—H⋯O hydrogen bonds and N—O⋯π interactions [O⋯centroid distances = 3.478 (1) and 3.238 (1) Å] dominate the packing, forming infinite zigzag chains along the b-axis direction. Neighbouring chains are linked together through C—H⋯O and C—H⋯Cl interactions. The absolute configuration of the two stereogenic centres was determined using the anomalous dispersion of the Cl atom.

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: KP2451).  (Michalska et al., 2012;Mathur et al., 2013).
Linezolid may also offer novel disease modifying and symptomatic therapeutic potential for the treatment of anxiety disorders (Jindal et al., 2013).

Experimental
The title compound was obtained as a by-product from the reaction of 4-[hydroxy(4-nitrophenyl)methyl]-1,3oxazolidin-2-one and benzenesulfonyl chloride with pyridine in chloroform. The synthesis process is described by Madesclaire et al. (2013). After isolation and purification by column chromatography, crystals suitable for X-ray analysis were obtained by slow evaporation from a mixture of ethyl acetate-cyclohexane (1:1 vol.) solution.

Refinement
H atoms were all found in a difference map, but those bonded to C were refined using a riding model with U iso (H) = 1.2 U eq (C) and C-H = 0.93-0.98 Å. The H atom bonded to N was freely refined. The highest peak and the deepest hole in the difference Fourier map are located 0.70 and 1.02 Å, respectively from C11 and C8 atoms. The absolute structure was determined on the basis of 2348 Friedel pairs.

Computing details
Data collection: APEX2 (Bruker, 2012); cell refinement: SAINT (Bruker, 2012); data reduction: SAINT (Bruker, 2012); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and PLATON (Spek, 2009); software used to prepare material for publication: publCIF (Westrip, 2010).    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 > σ(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.