| Popis: |
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 1a 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 |
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