Resolution of the enantiomers of various alpha-substituted ornithine and lysine analogs by high-performance liquid chromatography with chiral eluant and by gas chromatography on Chirasil-Val.
A reversed-phase high-performance liquid chromatography method, with L-proline and copper as chiral mobile phase, is described for the enantiomeric resolution of various alpha-substituted ornithine and lysine analogs. Although ornithine gives no separation with the chiral eluant used, excellent resolutions are obtained for various alpha-alkyl-, alpha-halogenomethyl-, alpha-vinyl-, and alpha-ethynyl-substituted ornithines. Similar separations are also observed for the dehydroornithine and lysine analogs. Gas chromatography on a chiral stationary phase, Chirasil-Val, allows the resolution of the ornithine and lysine analogs after derivatization into the monofluoroacyl derivatives of their corresponding lactams. No resolution or only a poor resolution is obtained by GC on Chirasil-Val for the dehydroornithine analogs as their di-N-perfluoroacyl alkyl esters. The chiral eluant HPLC procedure is easily scaled up for the semipreparative resolution of several ornithine analogs, i.e., alpha-fluoromethylornithine, alpha-difluoromethylornithine, alpha-chlorofluoromethylornithine, and alpha-fluoromethyldehydroornithine, which are known as potent ornithine decarboxylase inhibitors in vitro and in vivo.
D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D003300:Copper; D000518:Eflornithine / Q000031:analogs & derivatives / Q000302:isolation & purification; D007202:Indicators and Reagents; D008239:Lysine / Q000031:analogs & derivatives* / Q000302:isolation & purification; D009930:Organic Chemicals; D009952:Ornithine / Q000031:analogs & derivatives* / Q000302:isolation & purification; D065108:Ornithine Decarboxylase Inhibitors; D013237:Stereoisomerism
C041118:Chirasil-Val; D007202:Indicators and Reagents; D009930:Organic Chemicals; D065108:Ornithine Decarboxylase Inhibitors; C025025:alpha-methylornithine; C037000:2-fluoromethylornithine; D003300:Copper; D009952:Ornithine; D008239:Lysine; D000518:Eflornithine