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Separation of Diastereomers by Distillation—A New Procedure for the Synthesis of Optically Active Heterocyclic Carboxylic Acids
Author(s) -
FritzLanghals Elke
Publication year - 1993
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.199307531
Subject(s) - diastereomer , distillation , chemistry , recrystallization (geology) , enantiomer , boiling point , optically active , resolution (logic) , enantiomeric excess , carboxylic acid , organic chemistry , boiling , chromatography , enantioselective synthesis , catalysis , biology , computer science , paleontology , artificial intelligence
Resolution by distillation , in contrast to classical resolution by recrystallization, may be easy to perform. In the case of heterocyclic carboxylic acids 1 (X = O, S. n = 1,2), the diastereomeric amino acid amides 2 , which differ in boiling point by 7 K under reduced pressure, were separated by fractional distillation. Remarkably. both enantiomers of 2‐tetrahydrofurancarboxylic acid 1a (X = 0, n = 1) were obtained by the distillation of the diastereomers of 2a (R = i Pr. R′ = Me) with 99% optical purity.