Enantiomer separation by countercurrent chromatography using cinchona alkaloid derivatives as chiral selectors.
Cinchona-derived anion-exchange-type chiral selectors have been adapted and employed in countercurrent chromatography (CCC) for the separation of enantiomers of N-derivatized amino acids and 2-aryloxypropionic acids. The accurate optimization of the enantioseparation in terms of solvent system composition, pH values, ionic strength, and CCC operating conditions was performed. A wide range of solvent mixtures was evaluated. Successful resolutions were achieved in systems such as ammonium acetate buffer/tert-amyl alcohol/methanol/heptane and especially ammonium acetate buffer/methyl isobutyl ketone or diisopropyl ether. Up to 300 mg (0.92 mmol) of N-(3,5-dinitrobenzoyl)-(+/-)-leucine was totally resolved in a single run using a 10 mM concentration of chiral selector in 122 mL of stationary phase. This amount could be increased up to 900 mg (2.77 mmol) when pH-zone-refining mode was applied. The results here presented account for the high potential of CCC as a preparative enantiomer separation technique.
Franco
Pilar
P
Blanc
Javier
J
Oberleitner
Wolfgang R
WR
Maier
Norbert M
NM
Lindner
Wolfgang
W
Minguillón
Cristina
C
D000596:Amino Acids / Q000302:isolation & purification*; D002845:Chromatography / Q000379:methods*; D002930:Cinchona Alkaloids / Q000737:chemistry*; D004867:Equipment Design; D013237:Stereoisomerism
D000596:Amino Acids; D002930:Cinchona Alkaloids