(4R,5S)-4-Hydroxymethyl-5-[(methylsulfanyl)methyl]-1,3-oxazolidin-2-one

The title compound, C6H11NO3S, crystallizes utilizing a three-dimensional set of O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds. The 1,3-oxazolidin-2-one ring adopts an envelope conformation with the C atom bearing the hydroxymethyl group as the flap.

The title compound, C 6 H 11 NO 3 S, crystallizes utilizing a threedimensional set of O-HÁ Á ÁO, N-HÁ Á ÁO and C-HÁ Á ÁO hydrogen bonds. The 1,3-oxazolidin-2-one ring adopts an envelope conformation with the C atom bearing the hydroxymethyl group as the flap.
The full details of the synthesis of the title compound are presented elsewhere (Clinch et al., 2012).
The basic crystal packing can be described (Bernstein et al., 1995) with two C(5) motifs, corresponding to entries 1 and 3 in Table 1, which provide binding parallel to the bc and ab planes, respectively. The third interaction (entry 2, Table 1) makes an R 2 2 (14) motif in the ac plane utilizing a 2-fold axis ( Figure 2). The ability of the hydroxymethyl OH group to act as both donor (through its H atom) and acceptor (to adjacent nitrogen protons) is also observed in most of the related oxazolidinone structures.

Experimental
The preparation of the title compound is given by Clinch et al. (2012). Crystals were obtained by dissolving the title compound in a minimum volume of ethanol, adding hexanes until just before the turbidity point then setting aside at ambient temperature until crystallization was complete.

Refinement
All H atoms except those on C6 were refined with isotropic thermal parameters. The O3-HO3 bond was constrained to 0.82 Å using DFIX and the three H atoms on the methyl atom C6 were refined with a common isotropic thermal parameter.

Special details
Experimental. One backstop screened reflection (0,0,1) was omitted in the refinement; 1 other reflection (2,0,0) within sin(theta)/lambda of 0.5 was not collected. Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 > 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.