Optically Pure (<i>S</i>)-6,7-Dimethoxy-1,2,3,4-Tetrahydro-3-Isoquinolinecarboxylic Acid and Asymmetric Hydrogenation Studies Related to Its Preparation
作者:N. J. O'Reilly、W. S. Derwin、H. C. Lin
DOI:10.1055/s-1990-26936
日期:——
(S)-6,7-Dimethoxy-1,2,3,4-tetrahydro-3-isoquinolinecarboxylic acid has been prepared in optically pure form as its hydrochloride. Pictet-Spengler ring closure of the optically pure (S)-2-amino-3-(3,4-dimethoxyphenyl)propanoic acid hydrochloride salt (L-3,4-dimethoxyphenylalanine hydrochloride) proceeded without significant racemization. A simple and safe, asymmetric hydrogenation catalyst system has been developed which allows the rapid screening of various chiral phosphine ligands via an in situ ionic complex. A protocol was demonstrated which uses a statistical approach to consider the effects of changes in solvent, nitrogen substituent, oxygen substituent, and ligand in the asymmetric hydrogenation of alkyl or aryl (Z)-2-acylamino-3-(3,4-dimethoxyphenyl)-2-propenoate derivatives. This method was used to successfully determine the optimal substrate and conditions for the preparation of enantiomerically pure (S)-2-amino-3-(3, 4-dimethoxyphenyl)propanoic acid hydrochloride salt.
(S)-6,7-二甲氧基-1,2,3,4-四氢异喹啉-3-羧酸已以其氢氯酸盐的形式以光学纯态制备。光学纯的(S)-2-氨基-3-(3,4-二甲氧基苯基)丙酸氢氯酸盐(L-3,4-二甲氧基苯丙氨酸氢氯酸盐)通过Pictet-Spengler环闭合反应进行,未发生显著的消旋化。开发了一种简单且安全的非对称氢化催化体系,该体系允许通过原位离子配合物快速筛选各种手性膦配体。展示了一种采用统计方法的方案,考虑了溶剂、氮取代基、氧取代基和配体变化对烷基或芳基(Z)-2-酰氨基-3-(3,4-二甲氧基苯基)-2-丙烯酸酯衍生物非对称氢化反应的影响。该方法成功确定了制备光学纯(S)-2-氨基-3-(3,4-二甲氧基苯基)丙酸氢氯酸盐的最佳底物和条件。