Ethyl 1-phenyl-2-[4-(trifluoromethyl)phenyl]-1H-benzimidazole-5-carboxylate

The asymmetric unit of the title compound, C23H17F3N2O2, contains two molecules. In one of the molecules, the phenyl and triflouromethyl-substituted benzene rings form dihedral angles of 52.05 (8) and 33.70 (8)°, respectively, with the benzimidazole ring system, while the dihedral angle between them is 58.24 (10)°. The corresponding values in the other molecule are 58.40 (8), 25.90 (8) and 60.83 (10)°, respectively. In the crystal, molecules are linked into chains along [100] by C—H⋯O and C—H⋯N hydrogen bonds. Aromatic π–π stacking interactions [centroid–centroid distance = 3.6700 (12) Å] also occur.

In addition, the phenyl ring and the triflouromethyl-substituted phenyl ring form dihedral angles of 58.24 (10) and 60.83 (10)° in molecule A and B, respectively. Bond lengths and angles are within normal ranges and are comparable to related structure (Yoon et al., 2011;Kassim et al., 2012).

Experimental
Ethyl 3-amino-4-(phenyl amino) benzoate (0.84 mmol) and sodium metabisulfite adduct of trifluoromethyl benzaldehyde (1.68 mmol) were dissolved in DMF. The reaction mixture was reflux at 130 °C for 2 h. After completion, the reaction mixture was diluted in ethyl acetate (20 ml) and washed with water (20 ml). The organic layer was collected, dried over Na 2 SO 4 and the evaporated in vacuo to yield the product. The product was recrystallized from ethyl acetate as colourless blocks.

Refinement
All H atoms were positioned geometrically [C-H = 0.95-0.99 Å] and refined using a riding model with U iso (H) = 1.2 and 1.5 U eq (C). A rotating group model was applied to the methyl groups. In the final refinement, two outliers (0 2 0 and 0 0 2) were omitted.

Figure 1
The molecular structure of the title compound, showing 50% probability displacement ellipsoids.  The crystal packing of the title compound. The H atoms not involved in the intermolecular interactions (dashed lines) have been omitted for clarity.

Ethyl 1-phenyl-2-[4-(trifluoromethyl)phenyl]-1H-benzimidazole-5-carboxylate
Special details Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K. 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.