Chiral HPLC resolution of the Wieland-Miescher ketone and derivatives

The direct HPLC resolution of four structurally related compounds, the Wieland-Miescher ketone, the C(5) acetale homologue and their C(1) dioxolane derivatives, was studied on commercially available polysaccharide-based chiral stationary phases (CSPs) cellulose tris-(3,5-dimethylphenylcarbamate) (Chiralcel OD-H), native b-cyclodextrin (Cyclobond I), and acetylated, carboxymethylated and permethylated b-cyclodextrins. The retention, resolution and elution sequence of the enantiomeric couples were compared using different mobile phases. Baseline enantioseparation of all examined compounds was achieved only on the carboxymethyl-derivatized-cyclodextrin stationary phase, that appeared the more effective chiral selector for this class of compounds. Native, acetylated- and permethylated-cyclodextrin CSPs exhibited specific selectivity providing in general partial resolution of the compounds under investigation. On Chiralcel OD-H only two enantiomeric couples were fully separated. Elution orders depended on CPSs. To optimize chiral separation conditions the influence of mobile phase composition on column retention and selectivity was also investigated.