N-(2,6-Dimethylphenyl)-4-methylbenzamide

In the molecular structure of the title compound, C16H17NO, the two aromatic rings are close to orthogonal to each other [dihedral angle 78.8 (1)°], while the central –NH—C(=O)– amide core is nearly coplanar with the benzoyl ring, forming a dihedral angle of 3.5 (2)°. Intermolecular N—H⋯O hydrogen bonds in the crystal structure link the molecules into infinite chains running along the c axis of the crystal, and a C—H⋯O interaction also occurs.

In the molecular structure of the title compound, C 16 H 17 NO, the two aromatic rings are close to orthogonal to each other [dihedral angle 78.8 (1) ], while the central -NH-C( O)amide core is nearly coplanar with the benzoyl ring, forming a dihedral angle of 3.5 (2) . Intermolecular N-HÁ Á ÁO hydrogen bonds in the crystal structure link the molecules into infinite chains running along the c axis of the crystal, and a C-HÁ Á ÁO interaction also occurs.
Part of the crystal structure of (I), showing the formation of hydrogen-bonded chains (Table 1)

Experimental
The title compound was prepared according to the method described by Gowda et al. (2003). The purity of the compound was checked by determining its melting point. It was characterized by recording its infrared and NMR spectra. Needle-like colourless single crystals of the title compound were obtained by slow evaporation from an ethanol solution of the compound (0.5 g in about 30 ml of ethanol) at room temperature.

Refinement
All H atoms except amide H atom were placed in calculated positions with C-H distances in the range 0.93-0.96 Å and constrained to ride on their parent atoms. The C14 methyl group was refined as orientationally disordered using the instruction AFIX 127. Amide H atom was seen in difference map and was 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) or 1.5U eq (C-methyl). 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 e.s. 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.