5-Dimethylamino-N,N-dimethyl-2-nitrobenzamide

In the title compound, C11H15N3O3, one of the methyl groups attached to the benzamide unit is slightly twisted with a C—N—C—C torsion angle of 4.04 (13)°. The crystal packing is stabilized by weak intermolecular C—H⋯O hydrogen bonds together with a weak C—H⋯π interaction.

In the title compound, C 11 H 15 N 3 O 3 , one of the methyl groups attached to the benzamide unit is slightly twisted with a C-N-C-C torsion angle of 4.04 (13) . The crystal packing is stabilized by weak intermolecular C-HÁ Á ÁO hydrogen bonds together with a weak C-HÁ Á Á interaction.

Comment
Nitroaniline mustards are potential hypoxia-selective cytotoxic agents (Rauth, 1984) possessing reductive metabolism which activates the mustard nitrogen by converting the electron-withdrawing nitro group to an electron-donating hydroxylamine or amine (Brian et al., 1992). N-[(N,N-dimethylamino)ethyl]carboxamide derivatives proved to have excellent aqueous solubility and improved cytotoxic potency (Denny et al., 1986), but their reduction potentials, while higher than the non carboxamide compounds, were still low and have limited selectivity for hypoxic cells. (Palmer et al., 1990;Alston et al., 1983). These properties prompted us to synthesize the title compound.
In the asymmetric unit of (I), (Fig 1), one of the methyl group attached to the benzamide unit is slightly twisted as indicated by the torsion angle of C9-N1-C7-C6=4.04 (13)°. The benzene ring is essentially planar with the maximum deviation from planarity of 0.0117 (10)Å for the atom C5. The bond lengths and bond angles are normal (Allen et al., 1987).

Refinement
H atoms were positioned geometrically [C-H = 0.93-0.96 Å] and refined using a riding model, with U iso (H) = 1.2U eq (C) and 1.5U eq (methyl C). A rotating-group model was used for the methyl groups. Since there is no anamolous scattering effects, 2707 Friedel pairs were merged before final refinement.
The largest residual electron densities are located in the middle of some C-C bonds within the phenyl ring. Fig. 1. The molecular structure of the title compound, showing 50% probability displacement ellipsoids and the atom numbering scheme.

Special details
Experimental. The crystal was placed in the cold stream of an Oxford Cyrosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K. 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 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.