Optical resolution of a series of potential cholecystokinin antagonist 4(3H)-quinazolone derivatives by chiral liquid chromatography on α1-acid glycoprotein stationary phase

Optical resolution of the enantiomers of new 4(3H)-quinazolone derivatives is investigated using the α1-acid glycoprotein chiral stationary phase (Chiral-AGP). Stereoselective separation of the model compounds can be controlled by varying the pH and adding uncharged organic modifiers (acetonitrile and 2-propanol) to the mobile phase. For the majority of quinazolone derivatives, Chiral-AGP is proved to be an excellent enantioselector, because optimized chromatographic conditions allow for the baseline separation of the enantiomers. Separation factors between 1.19 and 1.85 are obtained. The effects of acetonitrile and 2-propanol on the chromatographic behavior of the model compounds are quite different because of their different hydrophobic- and hydrogen-bonding properties. The eluent pH and organic modifier concentration also contributes to the chiral recognition by altering the protein environment. The analysis of the experimental results leads to new information about the chromatographic mechanism on a Chiral-AGP surface.