Separation of enantiomers of norephedrine by capillary electrophoresis using cyclodextrins as chiral selectors: comparative CE and NMR studies.
In this study, the enantiomer migration order (EMO) of norephedrine (NEP) in the presence of various CDs was investigated by CE. NMR and CE techniques were used to analyze the mechanism of the chiral recognition between NEP enantiomers and four CDs, i.e., native α-CD, β-CD, heptakis(2,3-di-O-acetyl-6-O-sulfo)-β-CD (HDAS-β-CD), and heptakis(2,3-di-O-methyl-6-O-sulfo)-β-CD (HDMS-β-CD). EMO was reversed in the presence of α-CD and β-CD, although only minor differences in the structures of the complexes formed between NEP and these CDs could be derived from rotating frame nuclear Overhauser experiments (ROESY). The complexes between the enantiomers of NEP and the sulfated CDs, HDMS-β-CD, and HDAS-β-CD, were substantially different. However, EMO of NEP was identical in the presence of these CDs. HDAS-β-CD proved to be the most suitable chiral selector for the CE enantioseparation of NEP.
Institute of Physical and Analytical Chemistry, School of Exact and Natural Sciences, Tbilisi State University, Tbilisi, Georgia.
Ketevan
K
Lomsadze
Elena Domínguez
ED
Vega
Antonio
A
Salgado
Antonio L
AL
Crego
Gerhard K E
GK
Scriba
Maria Luisa
ML
Marina
Bezhan
B
Chankvetadze
D003505:Cyclodextrins / Q000737:chemistry*; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods*; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D010665:Phenylpropanolamine / Q000737:chemistry / Q000302:isolation & purification*; D013237:Stereoisomerism
D003505:Cyclodextrins; D010665:Phenylpropanolamine