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Synthesis 2008(6): 856-858  
DOI: 10.1055/s-2008-1032211
SHORTPAPER
© Georg Thieme Verlag Stuttgart · New York

An Improved Synthesis of (3R)-2-(tert-Butoxycarbonyl)-7-hydroxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylic Acid

Cong Liu, James B. Thomas, Larry Brieaddy, Bertold Berrang, F. Ivy Carroll*
Organic and Medicinal Chemistry, Research Triangle Institute, Research Triangle Park, NC 27709, USA
Fax: +1(919)5418868; e-Mail: fic@rti.org;
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Publication History

Received 30 October 2007
Publication Date:
28 February 2008 (online)

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Abstract

An improved synthesis of (3R)-2-(tert-butoxycarbonyl)-7-hydroxy-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid is described wherein a modified Pictet-Spengler reaction was employed to provide 95% yield of the product with 7% racemization or less. The enantiomeric excess of the final product was improved to 99.4% via recrystallization. The overall yield of this four-step synthesis provides the title compound in 43% starting from d-tyrosine.

Key words

Pictet-Spengler - 1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid - JDTic - synthesis