Effect of Multivalency on the Performance of Enantioselective Separation Media for Chiral HPLC Prepared by Linking Multiple Selectors to a Porous Polymer Support via Aliphatic Dendrons

Abstract

Chiral stationary phases (CSPs) containing L-proline indananilide chiral selectors attached through a multivalent dendritic linker to monodisperse macroporous poly(2-hydroxyethyl methacrylate-co-ethylene dimethacrylate) beads have been prepared using two different approaches. The convergent method involves the preparation of ligands in solution and their subsequent attachment to the support. The divergent approach is based on the stepwise "on-bead" formation of the linker using methods that are typical of solid-phase synthesis. While the convergent CSPs feature well-defined ligands, their loading is relatively low. In contrast, the divergent technique affords CSPs with higher loading but with more limited control over precise ligand architecture. Excellent enantioselectivities characterized by separation factors of up to 31 were achieved for the separation of racemic N-(3,5-dinitrobenzoyl)-alpha-amino acid alkyl amides with these new CSPs under normal-phase HPLC conditions.

Porous polymer particles—A comprehensive guide to synthesis, characterization, functionalization and applications

“…(Soap free) emulsion and dispersion polymerizations are readily utilized to obtain seeds. Since emulsion prepared seeds are generally in the submicron range, they are suitable for obtaining particles up to 10 µm in diameter after the suspension polymerization stage [68][69]. On the other hand, dispersion polymerized seeds can be in the range of 1-20 µm, thus 10-200 µm particles can be obtained in the suspension polymerization stage [70][71][72][73][74][75][76][77][78][79].…”

“…Seeded polymerizations seem to be suitable for production of SEC beads [427] since the pore size and pore size distribution can be easily controlled in the second swelling step. For HPLC columns, aerosol and precipitation [51,281] polymerizations are also available, together with seeded polymerizations [12,[68][69][428][429].…”

Methacrylate‐based chromatographic media

“…These values are much higher than those obtained for CSPs prepared earlier by a less controlled multistep process involving the reductive ring opening of GMA beads. Similar CPSs containing L-prolin indananilide chiral selector attached to the beads through a multivalent dendritic linker separated racemic N-(3,5-dinitrobenzoyl)-a-amino acid alkyl amides [179].…”

Synthesis of dendritic stationary phases with surface‐bonded L‐phenylalanine derivate as chiral selector and their evaluation in HPLC resolution of racemic compounds

“…the convergent, and the divergent ways. 19 In these CSPs, macroporous poly(2-hydroxyethyl methacrylate-co-ethylene dimethacrylate) beads were used as the supports. The CSP prepared in the convergent manner had relatively low loading, whereas the CSP prepared by divergent manner had comparatively higher loading.…”