2-Bromo-2-methyl-N-p-tolylpropanamide

In the title molecule, C11H14BrNO, there is twist between the mean plane of the amide group and the benzene ring [C(=O)—N—C C torsion angle = −31.2 (5)°]. In the crystal, intermolecular N—H⋯O and weak C—H⋯O hydrogen bonds link molecules into chains along [100]. The methyl group H atoms are disordered over two sets of sites with equal occupancy.

In the title molecule, C 11 H 14 BrNO, there is twist between the mean plane of the amide group and the benzene ring [C( O)-N-C . . . C torsion angle = À31.2 (5) ]. In the crystal, intermolecular N-HÁ Á ÁO and weak C-HÁ Á ÁO hydrogen bonds link molecules into chains along [100]. The methyl group H atoms are disordered over two sets of sites with equal occupancy.
RMF is grateful to the Spanish Research Council (CSIC) for the use of a free-of-charge licence to the Cambridge Structural Database (Allen, 2002). RMF and FZ also thank the Universidad del Valle, Colombia, and the Instituto de Química de Sã o Carlos, USP, Brazil, for partial financial support. The ATRP process (polymerization by atom transfer radical) allows control of the composition and functionality in polymerization reactions (Pietrasik & Tsarevsky, 2010). The use of functional initiators in these reactions allows the synthesis of new materials. Most initiators for ATRP processes are alkyl halides (Matyjaszewski & Xia, 2001;Kato et al., 1995). As part of our work related to functional initiators in polymerization processes (Moreno-Fuquen et al., 2011) we have determined the crystal structure of the title compound (I). The molecular structure of (I) is shown in Fig. 1. There is a twist between the mean plane of the amide group and benzene ring giving a C4-N1-C5-C6 torsion angle of -31.2 (5) °. In the crystal, intermolecular N-H···O and weak C-H···O hydrogen bonds link molecules into one-dimensional chains along [100] incorporating C(4) graph motifs (Etter, 1990) (see Table 1 and Fig. 2).

Experimental
The initial reagents were purchased from Aldrich Chemical Co. and were used as received. In a 100mL round bottom flask 4-methylaniline (3.173 mmoles, 0.340 g), triethylamine (0.635 mmol, 0.064 g) were mixed, then a solution of 2-bromo isobutiryl bromide (0.685 g) in anhydrous THF (5 ml) was added drop wise, under an argon stream. The reaction was carried out in a dry bag overnight under magnetic stirring. The solid was filtered off and dichloromethane (20 ml) added to the organic phase which was washed with brine (50 ml) followed by water (10 ml). The solution was concentrated at low pressure affording colourless crystals and recrystalized from a solution of hexane and ethyl acetate (80:20). M.p. 364 (1) K.

Refinement
The H-atoms were placed geometrically with C-H= 0.95 Å for aromatic, C-H = 0.98 Å for methyl and U iso (H) 1.2 and 1.5 times U eq of the parent atom respectively. The methyl group H atoms are disordered over two sets of sites with equal occupancy. Fig. 1. An ORTEP-3 (Farrugia, 1997) plot of (I) with displacement ellipsoids drawn at the 50% probability level. H atoms are shown as spheres of arbitary radius.

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 supplementary materials sup-3 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 > 2sigma(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.
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )