Molecules 2021 Aug 30;26(17). Epub 2021 Aug 30.
Department of Pharmacognosy, Semmelweis University, Üllői út 26, H-1085 Budapest, Hungary.
In order to better understand the chiral recognition mechanisms of positively charged cyclodextrin (CD) derivatives, the synthesis, the p determination by H nuclear magnetic resonance (NMR)-pH titration and a comparative chiral capillary electrophoretic (CE) study were performed with two series of mono-substituted cationic single isomer CDs. The first series of selectors were mono-(6--pyrrolidine-6-deoxy)-β-CD (PYR-β-CD), mono-(6--piperidine-6-deoxy)-β-CD (PIP-β-CD), mono-(6--morpholine-6-deoxy)-β-CD (MO-β-CD) and mono-(6--piperazine-6-deoxy)-β-CD (PIPA-β-CD), carrying a pH-adjustable moiety at the narrower rim of the cavity, while the second set represented by their quaternarized, permanently cationic counterparts: mono-(6--(-methyl-pyrrolidine)-6-deoxy)-β-CD (MePYR-β-CD), mono-(6--(-methyl-piperidine)-6-deoxy)-β-CD (MePIP-β-CD), mono-(6--(-methyl-morpholine)-6-deoxy)-β-CD (MeMO-β-CD) and mono-(6--(4,4--dimethyl-piperazine)-β-CD (diMePIPA-β-CD). Based on pH-dependent and selector concentration-dependent comparative studies of these single isomer -heterocyclic CDs presented herein, it can be concluded that all CDs could successfully be applied as chiral selectors for the enantiodiscrimination of several negatively charged and zwitterionic model racemates. Read More