2-[1-(4-tert-Butylphenyl)-4,5-diphenyl-1H-imidazol-2-yl]-4,6-dichlorophenol

An intramolecular O—H⋯N hydrogen bond helps to ensure near coplanarity of the 4,6-dichlorophenol and imidazole rings in the title compound.


Structure description
Imidazole is an active part of antifungal compounds like clotrimazole, ketoconazole, miconazole, isoconazole and econazole (Bastide et al., 1982). As part of our studies of imidazole derivatives, we now report the synthesis and crystal structure of the title compound, which consists of an imidazole ring bearing C10-C15 tert-butylphenyl, C4-C9 4,6-dichlorophenol and C20-C25 and C26-C31 phenyl rings (Fig. 1). The imidazole and the 4,6-dichlorophenol rings are close to coplanar with a dihedral angle of 8.89 (6) . The dihedral angles between the imidazole ring and the tert-butylphenyl ring and the C20and C26-phenyl rings are 85.18 (9), 81.22 (9) and 19.00 (8) , respectively. The C17, C18 and C19 carbon atoms of the tert-butyl group are disordered over two sets of sites in a 0.59:0.41 ratio. A short and presumably strong intramolecular O1-H1Á Á ÁN2 hydrogen bond is formed between the O1 atom of the 4,6-dichlorophenol ring and atom N2 of the imidazole ring (Table 1, Fig. 1), forming an S(6) ring, which helps to establish the near coplanarity of the imidazole and phenol rings.
In the crystal, pairwise C-HÁ Á ÁCl interactions involving atoms C29 of the phenyl ring and the Cl2 atom of the phenol group generate centrosymmetric R 2 2 (24) loops (Table 1, Fig. 2).

data reports Synthesis and crystallization
The title compound was synthesized by the one-pot reaction of benzil (10 mmol), 4-tert-butylaniline (10 mmol) and 3,5-dichloro-2-hydroxybenzaldehyde (10 mmol) with ammonium acetate (10 mmol) in a glacial acetic acid (20 ml) medium. The mixture was refluxed for 6 h at 343 K, the progress of the reaction being monitored by TLC. After completion of the reaction, the mixture was cooled to room temperature and poured into 100 ml of ice-cold water. The resulting precipitate was filtered, dried and further purified by column chromatography (7:3 petroleum ether:ethyl acetate) and isolated in good yield (85%). Colourless needles were recrystallized from methanol solution.

Figure 1
The molecular structure of the title compound with displacement ellipsoids drawn at the 50% probability level. The hydrogen bond is indicated by a double-dashed line.
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 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.