(R*)-Methyl 2-(2,6-dimethoxy-3,5-dinitrobenzamido)propanoate

In the title molecule, C13H15N3O9, the nitro groups are tilted with respect to the benzene mean plane by 22.8 (3) and 31.6 (3)°. The methoxy groups are in a cis orientation relative to the ring. In the crystal, molecules are linked by strong N—H⋯O hydrogen bonds into C(3) chains along [100].

In the title molecule, C 13 H 15 N 3 O 9 , the nitro groups are tilted with respect to the benzene mean plane by 22.8 (3) and 31.6 (3) . The methoxy groups are in a cis orientation relative to the ring. In the crystal, molecules are linked by strong N-HÁ Á ÁO hydrogen bonds into C(3) chains along [100].

Related literature
For the biological activity of related compounds or for their use as prodrugs, see: Sykes et al. (1999). For hydrogen-bond motifs, see: Bernstein et al. (1995).

Xiaofei Li and Yan Tong Comment
Amides and Imides widely exist in many biological activity compounds or could be used as prodrugs (Sykes et al., 1999).
We synthesized the title compound and shall examine its biological activity. In the title molecule, C 13 H 15 N 3 O 9 , the nitro groups are tilted with respect to the benzene mean plane by 22.8 (3) and 31.6 (3)°. The methoxy groups are cis conformation. In the crystal structure the molecules are linked by strong N-H···O (H···O 2.02 Å; N···O 2.850 (2) Å; N-H···O i 162° symmetry code: (i) 1+x, y, z) hydrogen bonds into C(3) chains along [100] (Bernstein et al., 1995).

Experimental
To a solution of D-alanine methyl ester hydrochloride (0.7 g, 5 mmol) and triethylamine (0.5 ml) in dry methylene chloride (100 ml) was added 2,6-dimethoxy-3,5-dinitrobenzoyl chloride 1.4 g, 5 mmol in dry methylene chloride (50 ml) at 0°C. The mixture was allowed to warm to room temperature for 1 h. After concentration the residue was subjected to chromatography (petroleum ether/ ethyl acetate, 3:1) to provide the product as a yellow crystal (1.3 g, 74.5%).

Refinement
The C-bound H-atoms were included in calculated positions and treated as riding atoms: C-H = 0.93, 0.96 and 0.98 Å for CH(aromatic), CH 3 and CH(methine) H-atoms, respectively, and N-H = 0.86 Å, with U iso (H)= k τimes U eq (parent Catom, N), where k = 1.5 for CH 3 H-atoms and k = 1.2 for all other H-atoms. Friedel pairs were merged and that absolute structure was determined relative to the known chiral centers.   Special details 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq C1 0.7640 (5