Chiral resolution of functionalized piperidine enantiomers by capillary electrophoresis with native, alkylated and anionic β-cyclodextrins

Abstract

Anionic sulfobutylether-β-CD (SBE-β-CD) has been found to be more suitable and convenient than native or alkylated β-CDs for the enantiomeric separation of functionalized piperidines. This anionic cyclodextrin derivative facilitates the separation of cationic enantiomers since the mobility of the complexed form is opposed to that of the free cation. The addition of low concentrations of SBE-β-CD (5–20 mg/ml) to the phosphate buffer, pH 2.6, allows a fast and baseline separation of dienomycine C ( R s=1.70) and also of 4-protected 2-alkylated piperidine ( R s=1.26) into their enantiomers. Compared to neutral CDs, this chiral selector offers the benefits of an increased aqueous solubility and a better resolution because this anionic CD acts as a countermigrating complexing agent versus cationic drugs.