3-(4-Bromophenyl)-1-butyl-5-[1-(2-chloro-6-methylphenyl)-1H-tetrazol-5-yl]imidazolidine-2,4-dione

In the title molecule, C21H20BrClN6O2, the chloro-substituted benzene ring forms a dihedral angle of 77.84 (7)° with the tetrazole ring and the bromo-substituted ring forms a dihedral angle of 43.95 (6)° with the imidazole ring. The dihedral angle between the tetrazole and imidazole rings is 67.42 (8)°. The terminal methyl group of the butyl substituent is disordered over two sets of sites, with refined occupancies 0.67 (3) and 0.33 (3). In the crystal, there is a short Br⋯N contact of 3.183 (2) Å.

In the title molecule, C 21 H 20 BrClN 6 O 2 , the chloro-substituted benzene ring forms a dihedral angle of 77.84 (7) with the tetrazole ring and the bromo-substituted ring forms a dihedral angle of 43.95 (6) with the imidazole ring. The dihedral angle between the tetrazole and imidazole rings is 67.42 (8) . The terminal methyl group of the butyl substituent is disordered over two sets of sites, with refined occupancies 0.67 (3) and 0.33 (3). In the crystal, there is a short BrÁ Á ÁN contact of 3.183 (2) Å .
The molecular structure is shown in Fig. 1. The terminal carbon of the butyl substituent is disordered between two positions, with occupancies that refine to 0.67 (3) for C14A and 0.33 (3) for C14B. As seen in Fig. 2, a short contact of 3.183 (2) Å is present between Br1 and N3 of a symmetry related tetrazole ring (0.5+x, 1.5-y, 0.5+z) with a C8-Br1-N3 angle of 174.57 (8)°. The van der Waals radii of the interacting atoms sum to 3.40 Å. The plane of the tetrazole ring (C1/N1-N4) makes a dihedral angle of 77.84 (7)° angle with the the plane of the neighboring chloro-substituted benzene ring (C15-C20). The imidazole ring (C2-C4/N5/N6) plane makes a dihedral angle of 43.95 (6)° relative to the plane of the bromo-substituted benzene ring (C5-C10) and the angle between the planes of the tetrazole and imidazole rings is 67.42 (8)°.

Refinement
All hydrogen atoms were visible in a difference Fourier map with the exception of those on the disordered terminal carbon of the butyl group and were added at calculated positions. Hydogen bond distances were set at 0.95 Å for aromatic H atoms, 0.99 Å for alkyl H atoms, and 0.98 Å for methyl H atoms. Themal parameters for all methyl hydrogen atoms were set to 1.50 times the isotropic equivalent thermal parameter of the atom to which they were attached. The thermal parameters of all other hydrogen atoms were set to 1.20 times the isotropic equivalent thermal parameter of the atom to which they were attached.

Computing details
Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: publCIF (Westrip, 2010).  The molecular structure of the title compound. Anisotropically refined atoms are shown as 50% probability ellipsoids.  Short contact between Br1 and N3 (3.1834 (1) Å). 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq Occ. (