(1R*,2S*)-2-Nitro-1-(4-nitrophenyl)propanol

The title compound, C9H10N2O5, presents a racemic mixture of two enantiomeric diastereomers. In the crystal, molecules assemble into zigzag chains parallel to the b axis [C(6) motif] due to the formation of elongated O—H⋯O(N) hydrogen bonds. Of interest is the fact that only the aliphatic nitro group is involved in hydrogen bonding and it adopts a gauche conformation with respect to the OH group.

Financial support from the Natural Science Foundation of China (project No. 21072228) is gratefully acknowledged. We are also grateful to Dr Maxim V. Borzov (a Foreign Expert at the North-West University, Xi'an, China) for his great help in revising this contribution.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: HG5165). The title compound, C 9 H 10 N 2 O 5 , I, belongs to the family of β-nitroalcohols which can serve as convenient synthetic precursors for a variety of 1,2-amino alcohols, amino sugars, nitroketones, nitroalkenes, ketones, and other practically important compounds (Palomo et al., 2005;Palomo, 2007).
β-Nitroalcohol I was prepared by a modified procedure described by Blay et al., 2008 (see Experimental). Only one pair of diastereomers is observed among the reaction products, what could be a result of the application of an enantiomerically pure base, natural quinine (see Experimental). In the unsymmetrical unit of I, the N-C(aliphatic) bond is by 0.05 Å longer than the N-C(aromatic) one due to the evident p-π conjugation. The aromatic NO 2 group is slightly twisted in respect to the Ph-ring plane [the C6/C7/N2/O4 dihedral angle equals to 17.9 (3)°]. In crystal lattice, the molecules of I assemble in zigzag chains parallel to the b-axis [a C(6) motif (Etter et al., 1990)
The hydroxy-group H-atom was found from the difference Fourier syntheses and refined isotropically.

Figure 1
Unsymmetrical unit of I with labeling. Thermal displacement ellipsoids are shown at the 50% probability level.

Figure 2
Chain-assembling of I in the crystal lattice (ball-and-stick drawing). Hydrogen bonds are depicted as dashed lines. Only O3, H3, and O1_i atoms are labeled. Symmetry code (i): -x, y + 1/2, -z + 1/2. 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.