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Amino Acids, XII: (±)Pipecolic Acid Derivatives ‐ Part 2: An Expedient Synthetic Entry to Substituted Pipecolic Acids
Author(s) -
Herdeis Claus,
Engel Wolfram
Publication year - 1992
Publication title -
archiv der pharmazie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.468
H-Index - 61
eISSN - 1521-4184
pISSN - 0365-6233
DOI - 10.1002/ardp.19923250709
Subject(s) - pipecolic acid , decarboxylation , chemistry , hydrolysis , amino acid , catalysis , derivative (finance) , stereochemistry , enantioselective synthesis , organic chemistry , biochemistry , financial economics , economics
The Diels‐Alder product 1 is transformed by Noyori reaction and catalytic hydrogenation to 4 . Hydrolysis with concomitant decarboxylation of 4 furnishes the trans configuration amino acid 5 . Functional group transformation (reduction, lactonization) of 5 provides 7 , ring opening affords the pipecolic acid derivative 9 . On the other hand 1 is hydrolyzed to 10 and 4‐oxo‐pipecolic acid 11 . Reduction of 10 and subsequent hydrolysis with decarboxylation of 12 affords the amino acid 13a /13b in a cis/trans ratio of 1:1. Contrary to this result, reduction of 11 provides 13a/13b in a ratio of ≧ 95/5.