Efficient Synthesis of Racemic and Enantiomerically Pure 1,2,3,4-Tetrahydroisoquinoline-3-carboxylic Acid and Esters
作者:B. O. T. Kammermeier、U. Lerch、Chr. Sommer
DOI:10.1055/s-1992-26325
日期:——
Racemic and optically pure 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acids and esters were prepared, via base-catalyzed cyclization of 1,2-bis (halomethyl) benzenes 1 a or b with diethyl 2-(acetylamino)malonate (2), subsequent decarboxylation and amide cleavage. The enantiomer resolution was achieved either by esterification with (-)-menthol followed by column chromatographic separation of the diastereomeric mixture or by diasteromeric salt separation of the benzylic ester with mandelic acid and base- catalyzed saponification of both esters.
在碱催化下,1,2-双(卤甲基)苯 1 a 或 b 与 2-(乙酰氨基)丙二酸二乙酯(2)发生环化反应,随后发生脱羧反应和酰胺裂解反应,制备出了外消旋和光学纯的 1,2,3,4-四氢异喹啉-3-羧酸及酯。对映体的分解是通过与(-)-薄荷醇酯化,然后柱层析分离非对映异构体混合物,或通过与扁桃酸分离苄酯的双酯盐,以及碱催化两种酯的皂化反应来实现的。