2-[2-(2-Nitrophenyl)-4,5-diphenyl-1H-imidazol-1-yl]-3-phenylpropan-1-ol

In the title compound, C30H25N3O3, the central imidazole ring forms dihedral angles of 77.34 (6), 12.56 (6) and 87.04 (6)°, respectively, with the o-nitrobenzene ring and the phenyl substituents in the 5- and 4-positions. The molecular conformation is stabilized by weak intramolecular C—H⋯π interactions. In the crystal, molecules are linked by O—H⋯N hydrogen bonds, forming chains running parallel to the b-axis direction.

In the title compound, C 30 H 25 N 3 O 3 , the central imidazole ring forms dihedral angles of 77.34 (6), 12.56 (6) and 87.04 (6) , respectively, with the o-nitrobenzene ring and the phenyl substituents in the 5-and 4-positions. The molecular conformation is stabilized by weak intramolecular C-HÁ Á Á interactions. In the crystal, molecules are linked by O-HÁ Á ÁN hydrogen bonds, forming chains running parallel to the b-axis direction.   Table 1 Hydrogen-bond geometry (Å , ).

Comment
Imidazole and its derivatives attracted research interest due to their important roles in the field of biology, medicine and chemistry. Imidazoles containing chiral N-substituent have high potentiality for application in coordination chemistry and transition metal catalysis (Ding et al., 2005;Heightman & Vasella, 1999;Wasserscheid & Keim, 2000). Our group is interested in the synthesis and application of chiral imidazolium compounds derived from natural amino acids (Gao, Yang et al., 2013;Gao, Wang et al., 2013;Mao et al., 2010;Yang et al., 2012;Xiao et al., 2012). Here we present the synthesis of a chiral nirtrophenyl-substituted imidazole derivative obtained from the condensation of a chiral aminoalcohol, nitrobenzaldehyde, ammonium acetate and benzyl. The synthetic procedure provides valuable information for the research and development of novel chiral catalysts.
Two intramolecular C-H···π interactions stabilizing the molecular conformation are observed (Table 1). In the crystal, molecules are linked by O-H···N hydrogen bonds (Table 1), forming chains running parallel to the b axis.

Experimental
L-Phenylalaninol (15.1 g, 0.1 mol) was added to the solvent (CH 3 OH, 200 mL) with ammonium acetate (7.7 g, 0.1 mol) and dibenzoyl (21.0 g, 0.1 mol) in a three-neck flask. The system was stirred until L-phenylalaninol was dissolved completely, affording a transparent dark yellow solution. The flask was then put into an ice bath and o-nitrobenzaldehyde (15.1 g, 0.1 mol) in MeOH (20 ml) was added dropwise to the solution. The mixture was heated to 65°C for 12 h. The solvent was eliminated by vacuum rotary evaporation and the crude product obtained purified using column chromatography (ethyl acetate/ethanol/triethylamine, 10:1:0.1 v/v/v). Crystallization of the product by slow evaporation of a methanol/diethyl ether solution (1:1 v/v) afforded crystals of the title compound suitable for X-ray analysis.

Refinement
The hydroxyl H atom was located in a difference Fourier map and refined freely. All other H atoms were placed in calculated positions with C-H = 0.93-0.98 Å and refined as riding, with U iso (H) = 1.2U eq (C).  The molecular structure of the title compound showing 30% probability displacement ellipsoids. Hydrogen atoms, but those associated to the chiral C29 carbon atom and hydroxyl group, are omitted for clarity.  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.