2-Ethoxy-6-[1-(3-ethoxy-2-hydroxybenzyl)-2,3-dihydro-1H-benzimidazol-2-yl]phenol acetonitrile monosolvate

The title compound, C24H24N2O4·CH3CN, a disubstituted benzimidazole, crystallized as an acetonitrile monosolvate. The benzene ring of the 2-ethoxy-6-methylphenol substiuent is approximately perpendicular to the nearly planar benzimidazole ring system [maximum deviation = 0.016 (1) Å], making a dihedral angle of 84.27 (8)°. The benzene ring of the 2-ethoxyphenol substituent is inclined to the benzimidazole mean plane by 29.68 (8)°. The dihedral angle between the benzene rings is 80.36 (9)°. In the molecule, there are strong O—H⋯N and O—H⋯O hydrogen bonds. In the crystal, molecules are connected by bifurcated O—H⋯(O,O) hydrogen bonds, forming chains propagating along [010].

The title compound contains a disubstituted benzimidazole molecule and a lattice solvent molecule (Fig. 1). One of the benzene rings (C17-C22) is approximately perpendicular to the nearly planar benzimidazole ring system [maximum deviation = 0.016 (1) Å], making a dihedral angle of 84.27 (8)°, whereas the other ring (C8-C13) is somewhat inclined to the benzomidazole mean plane with a dihedral angle of 29.68 (8)°. The dihedral angle between the benzene rings is 80.36 (9)°. The compound reveals strong intramolecular O-H···N and O-H···O hydrogen bonds, forming six-and fivemembered rings, respectively ( Fig. 1 and Table 1).
In the crystal, molecules are connected by bifurcated O-H···O,O hydrogen bonds, forming chains along the b axis ( Fig.   2 and Table 1).

Experimental
1,2-Phenylenediamine (0.7568 g, 6.998 mmol) and 3-ethoxysalicylaldehyde (2.3269 g, 14.003 mmol) in EtOH (20 ml) were stirred for 5 h at room temperature. After evaporation of the solvent, the residue was recrystallized from a mixture of acetone and ether (1:2, v:v) at 188 K, to give an orange powder (1.9139 g). Orange block-like crystals, suitable for Xray analysis, were obtained by slow evaporation of a CH 3 CN/acetone solution at room temperature.

Refinement
The hydroxy H atoms were located from a difference Fourier map and refined freely. C-bound H atoms were included in calculated positions and treated as riding atoms: C-H = 0.95, 0.98 and 0.99 Å for CH, CH 3 and CH 2 H-atoms, respectively, with U iso (H) = k× U eq (parent C-atom), where k = 1.5 for CH 3 H-atoms and = 1.2 for other H-atoms.  The molecular structure of the title compound, with atom numbering. Displacement ellipsoids are drawn at the 40% probability level. Intramolecular hydrogen-bonds are shown as dashed lines (see Table 1 for details).

Figure 2
A partial view along the a axis of the crystal packing of the title compound. Intra-and intermolecular O-H···N and O-H···O hydrogen-bonds are shown as dashed lines (see Table 1 for details).   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.