Efficient Synthesis of Racemic and Enantiomerically Pure 1,2,3,4-Tetrahydroisoquinoline-3-carboxylic Acid and Esters
- 1 January 1992
- journal article
- research article
- Published by Georg Thieme Verlag KG in Synthesis
- Vol. 1992 (11) , 1157-1160
- https://doi.org/10.1055/s-1992-26325
Abstract
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.Keywords
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