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Aminolysis of α‐hydroxy acid esters with α‐amino acid salts; first step in the synthesis of optically active 2,5‐morpholinediones
Author(s) -
Jörres Volker,
Keul Helmut,
Höcker Hartwig
Publication year - 1998
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/(sici)1521-3935(19980501)199:5<825::aid-macp825>3.0.co;2-w
Subject(s) - aminolysis , optically active , chemistry , organic chemistry , polymer chemistry , amino acid , combinatorial chemistry , catalysis , biochemistry
A process for preparing optically active 2,5‐morpholinediones 1 is described starting from optically active α‐amino acids and optically active α‐hydroxy esters. The process involves three steps: In the first step the sodium salt of an α‐amino acid is condensed with an α‐hydroxy ester to yield an optically active N ‐(α‐hydroxy acyl)‐α‐amino acid 4 . In the second step the hydroxy acid obtained is subjected to esterification with ethanol. In the third step the N ‐(α‐hydroxy acyl)‐α‐amino acid ethyl ester 5 is subjected to cyclization with an acidic catalyst. For some examples the cyclization was also performed directly from the hydroxy acid 4 . Morpholinediones 1 are useful as precursors for the preparation of poly(depsipeptides) 2 and copolymers containing depsipeptide repeating units.