A (4R)-hydroxy-L-proline-derived chiral scaffold and its oligomers as chiral selectors in liquid chromatography chiral stationary phases for enantioseparation

The chromatographic behaviour of a poly-L-proline-derived chiral stationary phase (CSP) is compared to the corresponding single proline-derived CSP. Structurally diverse racemic test compounds and mobile phases, including normal- and RP conditions, were used. Although the application domain of the poly-L-proline-derived CSP (CSP-3) was considerably restricted, this CSP showed a higher retention and a slightly broader application domain than the monomeric analogue (CSP-1) when heptane/2-PrOH was used as mobile phase. The presence of an alcohol in the mobile phase was essential for enantioseparation in the poly-L-proline-derived CSP when normal-phase conditions were applied.