Ethyl 4-[3-(1H-imidazol-1-yl)propylamino]-3-nitrobenzoate

In the title compound, C15H18N4O4, the 1H-imidazole ring forms a dihedral angle of 67.12 (8)° with the benzene ring. An S(6) ring motif is formed via an intramolecular N—H⋯O hydrogen bond. In the crystal, neighbouring molecules are linked by a pair of intermolecular N—H⋯N hydrogen bonds, forming an inversion dimer. The dimers are further linked by a pair of C—H⋯O hydrogen bonds, leading to the formation of chain along [021]. A C—H⋯π interaction involving the centroid of the benzene ring is also observed between the chains.

In the title compound, C 15 H 18 N 4 O 4 , the 1H-imidazole ring forms a dihedral angle of 67.12 (8) with the benzene ring. An S(6) ring motif is formed via an intramolecular N-HÁ Á ÁO hydrogen bond. In the crystal, neighbouring molecules are linked by a pair of intermolecular N-HÁ Á ÁN hydrogen bonds, forming an inversion dimer. The dimers are further linked by a pair of C-HÁ Á ÁO hydrogen bonds, leading to the formation of chain along [021]. A C-HÁ Á Á interaction involving the centroid of the benzene ring is also observed between the chains.

Refinement
Atom H1N1 was located in a difference Fourier map and was refined freely. The remaining H atoms were positioned geometrically and refined using a riding model, with U iso (H) = 1.2 or 1.5U eq (C) (C-H = 0.93-0.97 Å). A rotating group model was applied to the methyl group. Three outliners were omitted for the final refinement, 0 -1 4, -5 0 4 and -4 0 5.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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 O1 0.70039 (15