Five noncommercial and four commercially availabie cyclodextrin (CD) derivatives were tested as chiral auxiliaries for the capillary electrophoretic (CE) resolution of racemic 1,1'-bi-(2-naphthol) (BN), 1,1'-binaphthyl-2,2'-diyl hydrogenphosphate (BNHP), and 1,1'-binaphthyl-2,2'-diamine (BNA) at pH 4.0, 6.5, and 8.6. The noncommercial CDs were ethyloxycarbonyl-×-CD (ethylcarbonate-×{CD), dimethyiamino ethyloxycarbonylP-CD, a mercaptosuccinic acid derivative of P-CD, a maleic acid derivativi of P-CD and heptakis(6-deoxy-6-amino)-P-CD derivativi with one amino group on the C-6 carbon of each giucose unit. Except for the latter, the remaining derivatives were synthesized for this work. Also commercially availabie methyi-Ò-CD, hydroxypropyl-Ò-CD and the native Ò- and -×-CDs were examined. Among the nine CDs tested, the maleic acid derivative of Ò-CD gave the most interesting performances, since it resolved the atropisomers of BNA and BNHP in the same electrophoretic run at pH 4.0. It resolved the BNA racemate also at pH 6.5. Both the negatively charged CD tested were found to resolve anionic BNHP enantiomers, while positively charged CDs did not with cationic BNA. Several of the CDs investigated in this work were found to resolve the BNHP racemate, although at nonoptimal concentration. None of the experimented CDs was found to resolve the electrically neutral BN atropisomers pair at the three pHs considered, while some among these nine, experimented in a previous work, did so at higher pH
pH-dependent cyclodextrin capillary electrophoresis resolution of atropisomers
2003
Abstract
Five noncommercial and four commercially availabie cyclodextrin (CD) derivatives were tested as chiral auxiliaries for the capillary electrophoretic (CE) resolution of racemic 1,1'-bi-(2-naphthol) (BN), 1,1'-binaphthyl-2,2'-diyl hydrogenphosphate (BNHP), and 1,1'-binaphthyl-2,2'-diamine (BNA) at pH 4.0, 6.5, and 8.6. The noncommercial CDs were ethyloxycarbonyl-×-CD (ethylcarbonate-×{CD), dimethyiamino ethyloxycarbonylP-CD, a mercaptosuccinic acid derivative of P-CD, a maleic acid derivativi of P-CD and heptakis(6-deoxy-6-amino)-P-CD derivativi with one amino group on the C-6 carbon of each giucose unit. Except for the latter, the remaining derivatives were synthesized for this work. Also commercially availabie methyi-Ò-CD, hydroxypropyl-Ò-CD and the native Ò- and -×-CDs were examined. Among the nine CDs tested, the maleic acid derivative of Ò-CD gave the most interesting performances, since it resolved the atropisomers of BNA and BNHP in the same electrophoretic run at pH 4.0. It resolved the BNA racemate also at pH 6.5. Both the negatively charged CD tested were found to resolve anionic BNHP enantiomers, while positively charged CDs did not with cationic BNA. Several of the CDs investigated in this work were found to resolve the BNHP racemate, although at nonoptimal concentration. None of the experimented CDs was found to resolve the electrically neutral BN atropisomers pair at the three pHs considered, while some among these nine, experimented in a previous work, did so at higher pHI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
