Complementary enantioselectivity profiles of chiral cinchonan carbamate selectors with distinct carbamate residues and their implementation in enantioselective two-dimensional high-performance liquid chromatography of amino acids
| Autor: | Michael Lämmerhofer, Martina Ferri, Wolfgang Lindner, Ulrich Woiwode, Norbert M. Maier |
|---|---|
| Přispěvatelé: | Department of Chemistry |
| Rok vydání: | 2018 |
| Předmět: |
Carbamate
medicine.medical_treatment 116 Chemical sciences Chiral stationary phase ANION-EXCHANGERS 01 natural sciences Biochemistry High-performance liquid chromatography Analytical Chemistry Column chromatography medicine Cinchona STRATEGY Amino Acids Chromatography High Pressure Liquid Principal Component Analysis Chromatography Quinine two-dimensional chromatography DERIVATIVES 010405 organic chemistry Chemistry Elution 010401 analytical chemistry Organic Chemistry RECOGNITION Enantioselective synthesis ENANTIOSEPARATION STATIONARY PHASES Stereoisomerism General Medicine Combinatorial chemistry Quinidine 0104 chemical sciences Multidimensional HPLC separations RESOLUTION Two-dimensional chromatography Reagent SEPARATION Quinolines Carbamates HPLC Enantiomer |
| Zdroj: | Journal of chromatography. A. 1558 |
| ISSN: | 1873-3778 |
| Popis: | A cardinal requirement for effective 2D-HPLC separations is sufficient complementarity in the retention profiles of first and second dimension separations. It is shown that retention and enantioselectivity of chiral selectors derived from cinchona alkaloids can be conveniently modulated by structural variation of the carbamate residue of the quinine/quinidine carbamate ligand of such chiral stationary phases (CSP). A variety of aliphatic and aromatic residues have been tested in comparison to non-carbamoylated quinine CSP. Various measures of orthogonality have been utilized to derive the CSP that is most complementary to the tert-butylcarbamoylated quinine CSP (tBuCQN CSP), which is commercially available as Chiralpak QN-AX column. It turned out that O-9-(2,6-diisopropylphenylcarbamoyl)-modified quinine is most promising in this respect. Its implementation as a complementary CSP for the separation of amino acids derivatized with Sanger’s reagent (2,4-dinitrophenylated amino acids) in the first dimension combined with a tBuCQN CSP in the second dimension revealed successful enantiomer separations in a comprehensive chiral×chiral 2D-HPLC setup. However, the degree of complementarity could be greatly enhanced when simultaneously the absolute configurations were exchanged from quinine to quinidine in the chiral selector of the first dimension separation resulting in opposite elution orders of the enantiomers in the two dimensions. The advantage of such a chiral×chiral over achiral×chiral 2D-HPLC setup, amongst others, is the perfect compatibility of the mobile phase because in both dimensions the identical eluent can be used. |
| Databáze: | OpenAIRE |
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