Facile Preparation of optically Pure (3S)- and (3R)- 1, 2, 3, 4-Tetrahydroisoquinoline-3-carboxylic Acid
作者:KIMIAKI HAYASHI、YASUHIKO OZAKI、KENICHI NUNAMI、NAOTO YONEDA
DOI:10.1248/cpb.31.312
日期:——
Optically pure (3S)-1, 2, 3, 4-tetrahydroisoquinoline-3-carboxylic acid (1) was easily obtained by fractional crystallization of its benzyl ester (2b) p-toluenesulfonate, which was prepared from partially racemized 1 hydrochloride, followed by catalytic debenzylation. Similarly, (3R)-1 was prepared by the same procedure. The degree of racemization during the Pictet-Spengler reaction using optically active phenylalanine was determined by 1H-nuclear magnetic resonance (1H-NMR) spectroscopy of the corresponding methyl ester (2a), derived from the reaction product (1), in the presence of a chiral shift reagent.
光学纯的(3S)-1, 2, 3, 4-四氢异喹啉-3-羧酸(1)通过对其苄基酯(2b)的分馏结晶法轻松获得,该苄基酯是由部分消旋的1盐酸盐制备而成,随后经过催化去苄基化。同样,(3R)-1也是通过相同的程序制备的。在使用光学活性的苯丙氨酸进行Pictet-Spengler反应时,通过在存在手性位移试剂的情况下,对反应产物(1)所得到的相应甲基酯(2a)进行1H核磁共振(1H-NMR)光谱分析,确定了消旋化的程度。