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Enantioseparation of phenylalanine analogs on a quinine‐based anion‐exchanger chiral stationary phase: Structure and temperature effects
Author(s) -
Török Roland,
Berkecz Robert,
Péter Antal
Publication year - 2006
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.200600100
Subject(s) - chemistry , enantiomer , phenylalanine , enthalpy , gibbs free energy , cinchona , substituent , chiral stationary phase , ion exchange , chromatography , organic chemistry , ion , thermodynamics , enantioselective synthesis , biochemistry , physics , amino acid , catalysis
Application of a cinchona alkaloid‐based chiral anion‐exchanger stationary phase for the direct high‐performance liquid chromatographic enantioseparation of N ‐protected unusual phenylalanine analogs is reported. The N ‐benzyloxycarbonyl, N ‐3,5‐dinitrobenzyloxycarbonyl, N ‐benzoyl and N ‐3,5‐dinitrobenzoyl derivatives were well separable with high resolution. To achieve optimal separation of the enantiomers, the chromatographic conditions and temperature were varied. Linear van't Hoff plots were observed in the studied temperature range, 278–343 K, and the apparent changes in enthalpy, Δ(Δ H °), entropy, Δ(Δ S °), and Gibbs free energy, Δ(Δ G °), were calculated. The values of the thermodynamic parameters depended on the nature of the N ‐acyl groups, on the structures of the compounds, and especially on the nature of the substituent on C3 of phenylalanine.