4-[6,8-Dibromo-2-(2-chloro-5-nitrophenyl)-1,2,3,4-tetrahydroquinazolin-3-yl]cyclohexanol

The title compound, C20H20Br2ClN3O3, was synthesized by the condensation reaction of 2-chloro-5-nitrobenzaldehyde with 4-(2-amino-3,5-dibromobenzylamino)cyclohexanol in a methanol solution. There are two independent molecules in the asymmetric unit and in one molecule the atoms of the cyclohexane ring are disordered over two sets of sites with refined occupancies of 0.657 (12) and 0.343 (12). The dihedral angle between the two benzene rings is 89.5 (2)° in one molecule and 82.9 (2)° in the other. In the crystal structure, intermolecular N—H⋯O and O—H⋯O hydrogen bonds link the molecules into chains propagating along [01].


Related literature
There are two independent molecules in the asymmetric unit of the title compound, Fig. 1. The dihedral angle between the two benzene rings is 89.5 (2)° in one molecule and 82.9 (2)° in the other. The cyclohexyl rings adopt chair configurations.
All bond lengths are within normal ranges (Allen et al., 1987).
Experimental 2-Chloro-5-nitrobenzaldehyde (1.0 mol, 185.6 mg) and 4-(2-amino-3,5-dibromobenzylamino)cyclohexanol (1.0 mmol, 378.1 mg) were dissolved in a methanol solution (30 ml). The mixture was stirred at room temperature to give a clear colorless solution. Crystals of the title compound were formed by gradual evaporation of the solvent for a week at room temperature.

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.