N-(3-Bromo-2-methylphenyl)-2-oxo-1,2-dihydropyridine-3-carboxamide

The title compound, C13H11BrN2O2, consists of two six-membered rings linked by an amide group and adopts a near planar conformation. The dihedral angle between the two rings is 8.38 (11)°. In the crystal structure, there are intra- and intermolecular N—H⋯O hydrogen bonds, the latter forming inversion dimers.

The title compound, C 13 H 11 BrN 2 O 2 , consists of two sixmembered rings linked by an amide group and adopts a near planar conformation. The dihedral angle between the two rings is 8.38 (11) . In the crystal structure, there are intra-and intermolecular N-HÁ Á ÁO hydrogen bonds, the latter forming inversion dimers.

Related literature
For a related structure, see: Long et al. (2006). For background and details of synthesis, see: Ting et al. (1990 Table 1 Hydrogen-bond geometry (Å , ). (II) (Fig. 1, Table 1). The two aromatic rings of the molecule are linked by an amide group. Due to the extended πconjugation system throughout the whole molecule via the amide bridge, the molecule takes a near planar conformation.
The dihedral angle between the two aromatic rings is 8.38 (11)°.
Experimental 2-Chloronicotinic acid (1.9 g, 12.1 mmol), 3-bromo-2-methyl-aniline (2.5 g, 13.4 mmol), and pyridine (1.0 ml, 12 mmol) were added to a round-bottom flask, followed by introduction of p-toluenesulfonic acid (0.3 g, 1.8 mmol) in 10 ml of water. The resulted solution was refluxed overnight. Colorless solid precipitated out after the mixture was cooled down to room temperature, and it was characterized by NMR to be the title compound (I). Crystals were grown from MeOH solution by slow evaporation.

Refinement
H atoms were located in difference Fourier maps and subsequently placed in idealized positions with constrained C-H distances of 0.95 (C Ar -H), 0.98 (C Me -H) and 0.88 Å (N-H). U iso (H) values were set to 1.2U eq (C,N) or 1.5U eq (C) for methyl group.  The molecular structure of (I), with displacement ellipsoids drawn at the 50% probability level (arbitrary spheres for the H atoms).

Figure 2
Tautomerism of the title compound. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 0.94 e Å −3 Δρ min = −0.61 e Å −3 Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 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.