N-(2,6-Dimethylphenyl)-3-methylbenzamide

In the molecular structure of the title compound, C16H17NO, the N—H and C=O bonds are anti to each other. The two aromatic rings make a dihedral angle of 73.3 (1)°. In the crystal, intermolecular N—H⋯O hydrogen bonds connect the molecules into C(4) chains running along the c axis.

In the molecular structure of the title compound, C 16 H 17 NO, the N-H and C O bonds are anti to each other. The two aromatic rings make a dihedral angle of 73.3 (1) . In the crystal, intermolecular N-HÁ Á ÁO hydrogen bonds connect the molecules into C(4) chains running along the c axis.
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.

Comment
As part of a study of the substituent effects on the crystal structures of benzanilides (Gowda et al., 2008a(Gowda et al., ,b, 2009, in the present work, the structure of N-(2,6-dimethylphenyl)3-methylbenzamide (I) has been determined. In the structure, the conformations of the N-H and C=O bonds are anti to each other ( Fig. 1), similar to those observed in N-(phenyl)3-methylbenzamide (II) (Gowda et al., 2008a), N-(2,6-dimethylphenyl)2-methylbenzamide (III) (Gowda et al., 2008b), N-(2,6-dichloromethylphenyl)-3-methylbenzamide (IV) (Gowda et al., 2009) and the parent benzanilide (Bowes et al., 2003). Further, the conformation of the C=O bond in (I) is syn to the meta-methyl substituent in the benzoyl ring, similar to that observed in (III) and (IV), but contrary to the anti conformation observed between the C=O bond and the meta-methyl group in the benzoyl ring of (II).

Experimental
The title compound was prepared according to the literature method (Gowda et al., 2008a,b). The purity of the compound was checked by determining its melting point. It was characterized by recording its infrared and NMR spectra. Single crystals of the title compound used in X-ray diffraction studies were obtained from a slow evaporation of its ethanolic solution at room temperature.

Refinement
H atoms bounded to carbon atoms were positioned with idealized geometry using a riding model with C-H = 0.93 Å or 0.96 Å. The coordinates of the amide H atom were refined with the N-H distance restrained to 0.86 (2) Å. The U iso (H) values were set at 1.2U eq (C aromatic , N) and 1.5U eq (C methyl ). In the absence of significant anomalous scattering, the absolute structure could not be reliably determined and Friedel pairs were merged. Any references to the Flack parameter were removed. Fig. 1. Molecular structure of (I) showing the atom labelling scheme. Displacement ellipsoids are drawn at the 30% probability level and H atoms are represented as small spheres of arbitrary radii.

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.