Chiral Benzofurazan-Derived Derivatization Reagents for Indirect Enantioseparations by HPLC

The separation of enantiomers of biologically important molecules, such as chiral pharmaceuticals and amino acids, is an important issue because a significant difference in the activity of the enantiomers is usually observed in biological systems. Chiral separations can be carried out by so-called direct methods or by indirect methods following derivatization with a chiral reagent. Many such chiral labeling reagents have been developed for various functional groups, such as amino groups, carboxyl groups, thiols, and hydroxyl groups. This chapter describes methodologies for the indirect HPLC determination of chiral molecules, based upon diastereomer formation. The derivatization, separation, and detection procedures with the chiral benzofurazan-bearing reagents, i.e., 4-(3-aminopyrrolidin-1-yl)-7-(N,N -dimethylaminosulfonyl)-2,1,3-benzoxadiazole (DBD-APy) and 4-(3-isothiocyanatopyrrolidin-1-yl)-7-(N,N -dimethylaminosulfonyl)-2,1,3-benzoxadiazole (DBD-PyNCS), are described as representative examples.