N-(1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-2-(4-nitrophenyl)acetamide

In the title compound, C19H18N4O4, the nitrophenyl and phenyl rings are twisted by 67.0 (6) and 37.4 (4)°, respectively, with respect to the pyrazole ring plane [maximum deviation = 0.0042 (16) Å]. The dihedral angle between the mean planes of the phenyl rings is 59.3 (3)°. The amide group, with a C—N—C—C torsion angle of 177.54 (13)°, is twisted away from the plane of the pyrazole ring in an antiperiplanar conformation. In the crystal, N—H⋯O hydrogen bonds involving the carbonyl group on the pyrazole ring and the amide group, together with weak C—H⋯O interactions forming R 2 2(10) graph-set motifs, link the molecules into chains along [100]. Additional weak C—H⋯O interactions involving the nitrophenyl rings further link the molecules along [001], also forming R 2 2(10) graph-set motifs, thereby generating (010) layers.

In the title compound, C 19 H 18 N 4 O 4 , the nitrophenyl and phenyl rings are twisted by 67.0 (6) and 37.4 (4) , respectively, with respect to the pyrazole ring plane [maximum deviation = 0.0042 (16) Å ]. The dihedral angle between the mean planes of the phenyl rings is 59.3 (3) . The amide group, with a C-N-C-C torsion angle of 177.54 (13) , is twisted away from the plane of the pyrazole ring in an antiperiplanar conformation. In the crystal, N-HÁ Á ÁO hydrogen bonds involving the carbonyl group on the pyrazole ring and the amide group, together with weak C-HÁ Á ÁO interactions forming R 2 2 (10) graph-set motifs, link the molecules into chains along [100]. Additional weak C-HÁ Á ÁO interactions involving the nitrophenyl rings further link the molecules along [001], also forming R 2 2 (10) graph-set motifs, thereby generating (010) layers.
MK is grateful to the CPEPA-UGC for the award of a JRF and thanks the University of Mysore for research facilities. JPJ acknowledges the NSF-MRI program (grant No. CHE-1039027) for funds to purchase the X-ray diffractometer.
Supporting information for this paper is available from the IUCr electronic archives (Reference: HG5393).  (Mijin et al., 2006(Mijin et al., , 2008. Amides are also used as ligands due to their excellent coordination abilities (Wu et al., 2008(Wu et al., , 2010. In a variety of biological heterocyclic compounds, N-pyrazole derivatives are of great interest because of their chemical and pharmaceutical properties . Some of the Npyrazole derivatives have been found to exhibit good insecticidal activities (Hatton et al., 1993), antifungal activities (Liu et al., 2010) and non-linear optical properties (Chandrakantha et al., 2013). Crystal structures of some related acetamide and pyrazole derivatives including: (Fun et al., 2012)  and recently N-(1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-2-phenylacetamide (Kaur et al., 2013) have been reported. In view of the importance of amide derivatives of pyrazoles, this paper reports the crystal structure of the title compound (I), The title compound, (I), C 19 H 18 N 4 O 4 , crystallizes with one independent molecule in the asymmetric unit ( Fig. 1). In the molecule, the pyrazole ring is nearly planar with C9 atom showing a maximum deviation of 0.0042 (16)Å. The mean planes of the 4-nitrophenyl and phenyl rings is twisted with respect to that of the pyrazole ring by 67.0 (6)° and 37.4 (4)°, respectively. The dihedral angle between the mean planes of the two phenyl rings is 59.3 (3)°. The amide group, with a torsion angle of 177.54° is twisted away from the plane of the pyrazole ring in an anti-periplanar conformation. Bond lengths are in normal ranges (Allen et al., 1987). Classical N-H···O intermolecular hydrogen bonds involving the pyrazole ring and the amide group along with weak C-H···O intermolecular interactions forming R 2 2 (10) graph set motifs link the molecules into chains along [100]. Additional weak C-H···O intermolecular interactions involving the nitrophenyl rings link the molecules further along [001] also forming R 2 2 (10) graph set motifs and further extending crystal packing into a 2-D supramolecular network (Fig. 2).

Experimental
4-Nitrophenylacetic acid (0.181 g, 1 mmol) and 4-aminoantipyrine (0.203 g, 1 mmol), 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (1.0 g, 0.01 mol) and were dissolved in dichloromethane (20 mL). The mixture was stirred in presence of triethylamine at 273 K for about 3 h (Fig. 3). The reaction completion was confirmed by thin layer chormatography. The contents were poured into 100 ml of ice-cold aqueous hydrochloric acid with stirring, which was extracted thrice with dichloromethane. The organic layer was washed with a saturated NaHCO 3 solution and brine solution, dried and concentrated under reduced pressure to give the title compound, (I). Single crystals were grown from supplementary materials sup-2 Acta Cryst. (2014). E70, o636-o637 dichloromethane and and further recrystallised from methanol solution by the slow evaporation method which were subsequently used for x-ray studies.

Refinement
All of the H atoms were placed in their calculated positions and then refined using the riding model with Atom-H lengths of 0.93Å (CH); 0.97Å (CH 2 ); 0.96Å (CH 3 ) or 0.86Å (NH). Isotropic displacement parameters for these atoms were set to 1.2 (CH, CH 2 , NH)and 1.5 (CH 3 ) times U eq of the parent atom. Idealised Me refined as rotating group.

Figure 1
ORTEP drawing of (I) (C 19 H 18 N 4 O 4 ) showing the labeling scheme of the molecule with 30% probability displacement ellipsoids.  Synthesis scheme of (I). 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.