2,4-Dichloro-6-((1R)-1-{[(R)-(2-chlorophenyl)(cyclopentyl)methyl]amino}ethyl)phenol

In the title compound, C20H22Cl3NO, the five-membered ring adopts an envelope conformation, and the two benzene rings are oriented at a dihedral angle of 40.44 (9)°. Intramolecular O—H⋯N and N—H⋯Cl hydrogen bonding is present. In the crystal, the molecules are linked via weak intermolecular C—H⋯O hydrogen bonds.

In the title compound, C 20 H 22 Cl 3 NO, the five-membered ring adopts an envelope conformation, and the two benzene rings are oriented at a dihedral angle of 40.44 (9) . Intramolecular O-HÁ Á ÁN and N-HÁ Á ÁCl hydrogen bonding is present. In the crystal, the molecules are linked via weak intermolecular C-HÁ Á ÁO hydrogen bonds.

Comment
The chiral aminophenols containing some O and N atoms are of great interests due to their widespread application in asymmetric synthesis such as chiral bases, auxiliaries and ligands (Li et al., 2004;Puigjaner et al., 1999;Cimarelli et al., 2002).
The molecular structure of (I) is illustrated in Fig. 1. The title compoud has two chiral centers (C7/C9), which have configurations R, R, confirmed by the X-ray structural analysis. There are the intramolecular O-H···N and N-H···Cl hydrogen bonding which stablizes the conformation of the molecule (Table 1). In the crystal packing, the molecules are linked to each other via intermolecular C-H···O hydrogen bonds (Table 1).

Experimental
The title compound was prepared according to the procedure of Yang et al. (2005). (R)-1-(2-chlorophenyl)-1-cyclopentylmethanamine (0.9 mmol) and 1-(3,5-dichloro-2-hydroxyphenyl)ethanone (0.9 mmol) were dissolved in methanol (10 ml) and reacted at room temperature for 48 h. After removal of the solvent, NaBH 4 (4.5 mmol) was added to the solution in THF/ethanol (1:1 v/v, 20 ml) and stirred at 273 K until the solution became colourless. The solvent was then removed under reduced pressure. Water (10 ml) was added to the residue and 1 M HCl was added dropwise until hydrogen production ceased. The mixture was neutralized with aqueous solution of Na 2 CO 3 , then extracted with CHCl 3 , and the organic layer was dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure. Further purification was carried out by thin-layer silica-gel chromatography (chloroform) to give a colorless solid (yield 82.7%). Single crystals of (I) were grown from the n-hexane solution.

Refinement
Imino-H and hydroxy-H atoms were located in a difference Fourier map and refined as riding in as-found relative positions with U iso (H) = 1.2U eq (N,O). Other H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms with C-H = 0.93-0.98 Å, and refined in riding mode with U iso (H) = 1.5U eq (C) for mathyl H atoms and 1.2U eq (C) for the others.