Synthesis of (2R)-1-(4-Chloro-2-pyridyl)-2-(2-pyridyl)ethylamine: A Selective Oxime Reduction and Crystallization-Induced Asymmetric Transformation
作者:Shigeto Negi、Masayuki Matsukura、Masanori Mizuno、Kazutoshi Miyake、Norio Minami
DOI:10.1055/s-1996-4325
日期:1996.8
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”.
用锌在三氟乙酸中还原 1-(4-氯-2-吡啶基)-2-(2-吡啶基)乙酮肟 (3),得到相应的外消旋吡啶乙胺 4,收率极高,且无需还原去除氯原子。随后,在一定量的 3,5-二氯水杨醛催化下,用光学活性顺式环己烷羧酸衍生物对胺 4 进行非对映结晶,发现通过 "结晶诱导不对称转化 "得到了所需的 R-胺 6,产率为 42%。