Synthesis 1992; 1992(11): 1157-1160
DOI: 10.1055/s-1992-26325
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Efficient Synthesis of Racemic and Enantiomerically Pure 1,2,3,4-Tetrahydroisoquinoline-3-carboxylic Acid and Esters

B. O. T. Kammermeier* , U. Lerch, Chr. Sommer
  • *Hoechst AG, Allgemeine Pharma Forschung, 6230 Frankfurt/Main-80, Germany
Further Information

Publication History

Publication Date:
17 September 2002 (online)

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.