N-(2,5-Dimethylphenyl)-2-methylbenzamide

In the title compound, C16H17NO, the two aromatic rings are almost coplanar, making a dihedral angle of 1.9 (2)°. The amide group makes dihedral angles of 48.0 (3) and 48.6 (3)° with the 2-methylphenyl and the 2,5-dimethylphenyl rings, respectively. Intermolecular N—H⋯O hydrogen bonds link the molecules into chains running along the a axis of the crystal.

In the title compound, C 16 H 17 NO, the two aromatic rings are almost coplanar, making a dihedral angle of 1.9 (2) . The amide group makes dihedral angles of 48.0 (3) and 48.6 (3) with the 2-methylphenyl and the 2,5-dimethylphenyl rings, respectively. Intermolecular N-HÁ Á ÁO hydrogen bonds link the molecules into chains running along the a axis of the crystal.

Related literature
For related structures, see Gowda, Foro et al. (2008a,b); Gowda, Tokarčík et al. (2009 Table 1 Hydrogen-bond geometry (Å , ). MT and JK thank the Grant Agency of the Slovak Republic (VEGA 1/0817/08) and the Structural Funds, Interreg IIIA, for financial support in purchasing the diffractometer. VZR thanks the University Grants Commission, Government of India, New Delhi, for the award of a research fellowship determined.
The two aromatic rings are almost coplanar, with the dihedral angle of 1.9 (2)°. The amido group makes dihedral angles of 48.0 (3)° and 48.6 (3)° with the 2-methylphenyl and the 2,5-dimethylphenyl rings, respectively. In the crystal structure, the intermolecular N-H···O hydrogen bonds (Table 1) link the molecules into chains running along the a-axis of the crystal ( Fig. 2).

Experimental
The title compound was prepared according to the method described by Gowda, Foro et al. (2008b). The purity of the compound was checked by determining its melting point. It was characterized by recording its infrared and NMR spectra.
Block-like colourless single crystals of the title compound were obtained by slow evaporation from an ethanol solution (0.5 g in about 30 ml of ethanol) at room temperature.

Refinement
All hydrogen atoms were positioned with idealized geometry using a riding model with C-H = 0.93 Å or 0.96 Å and N-H = 0.86 Å. The U iso (H) values were set at 1.2U eq (C-aromatic, N) and 1.5U eq (C-methyl). The C16 methyl group exhibits orientational disorder in the positions of H atoms. In the last cycles of refinement, all H atoms were treated as riding on their parent atoms.
The two sets of methyl hydrogen atoms were refined with occupancies 0.74 (4) and 0.26 (4). In the absence of significant anomalous scattering, the absolute structure could not be reliably determined and then the Friedel pairs were merged and any references to the Flack parameter were removed.

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 > 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.