Synthesis of (2R)-1-(4-chloro-2-pyridyl)-2-(2-pyridyl)ethylamine: A selective oxime reduction and crystallization-induced asymmetric transformation

Article abstract of DOI:10.1055/s-1996-4325

Reduction of 1-(4-chloro-2-pyridyl)-2-(2-pyridyl)ethanone oxime (3) using zinc in trifluoroacetic acid gave the corresponding racemic pyridylethylamine 4 in excellent yield without reductive removal of the chlorine atom. A subsequent diastereomeric crystallization of the amine 4 with an optically active cis-cyclohexanecarboxylic acid derivative in the presence of a catalytic amount of 3,5-dichlorosalicylaldehyde was found to give the desired R-amine 6 in 42% yield via a 'crystallization-induced asymmetric transformation'.