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Novel enantioselective strong cation exchangers based on sulfodipeptide selectors: Evaluation for enantiomer separation of chiral bases by nonaqueous capillary electrochromatography
Author(s) -
Hebenstreit Dieter,
Bicker Wolfgang,
Lämmerhofer Michael,
Lindner Wolfgang
Publication year - 2004
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200305744
Subject(s) - capillary electrochromatography , diastereomer , enantiomer , chemistry , sulfonic acid , enantioselective synthesis , dipeptide , electrochromatography , chromatography , amino acid , chirality (physics) , capillary electrophoresis , combinatorial chemistry , organic chemistry , stereochemistry , catalysis , biochemistry , chiral symmetry breaking , physics , quantum mechanics , nambu–jona lasinio model , quark
Strong cation exchange (SCX)‐type chiral stationary phases (CSPs) based on β‐amino sulfonic acid‐terminated dipeptide derivatives as chiral selectors, immobilized on thiol‐modified silica particles (3.5 μm), were synthesized and applied to enantiomer separations of chiral bases by nonaqueous capillary electrochromatography (CEC). The effect of structural variations of the sulfodipeptide selectors on the separation factors α was investigated. These studies included variation of the acid‐terminal amino sulfonic acid residue, variation of the configurations, i.e. , comparison of the diastereomeric ( S , S )‐ and ( R , S )‐configurations of the sulfodipeptides, and finally comparison of sulfodipeptide selectors with corresponding β‐amino sulfonic acid analogs. In general, the capillary columns (100 μm ID) packed with the new SCX‐type CSPs showed enantioselectivity for an elaborated set of chiral basic drugs in CEC acting by an enantioselective cation‐exchange retention mechanism. N ‐[ N ‐(4‐Allyloxy‐3,5‐dichlorobenzoyl)‐leucyl]‐2‐amino‐3,3‐dimethylbutane sulfonic acid, in particular with ( R , S )‐configuration, turned out to be a more effective SCX‐type selector than a more rigid analog based on N ‐[ N ‐(4‐Allyloxy‐3,5‐dichlorobenzoyl)‐leucyl]‐2‐pyrrolidinemethane sulfonic acid. Both of the former diastereomers were capable to baseline‐resolve the enantiomers of ca. 40% of the tested basic chiral solutes including sympathomimetics and β‐blockers, while for the latter SCX‐type CSPs only 10–20% of the selected solutes afforded resolutions > 1.5.