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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 25, Number 2
BKCSDE 25(2)
February 20, 2004 

NMR Spectroscopic Analysis on the Chiral Recognition of Noradrenaline by β-Cyclodextrin ( β-CD) and Carboxymethyl- β-cyclodextrin (CM- β-CD)
Sanghoo Lee, Dong-heui Yi, Seunho Jung*
β-Cyclodextrin ( β-CD), Carboxymethyl- β-cyclodextrin (CM- β-CD), Chiral NMR shift agent, Noradrenaline (NA), NMR spectroscopic analysis
β-CD and CM- β-CD as chiral NMR shift agents were used to resolve the enantiomers of noradrenaline (NA). The stoichiometry of each complex formed between the CDs and the enantiomers of NA was found to be 1 : 1 through the continuous variation plots. The binding constants (K) of the complexes were determined from 1H NMR titration curves. This result indicated that both β-CD and CM- β-CD formed the complexes with the S(+)-NA more preferentially than its R(.)-enantiomer. The K values for the complexes with β-CD (KS(+) = 537 M.1 and KR(.) = 516 M.1) was larger than those with CM- β-CD (KS(+) = 435 M.1 and KR(.) = 313 M.1), however, enantioselectivity ( α) of S(+)- and R(.)-NA to CM- β-CD ( α = 1.38) was larger than that to β-CD ( α = 1.04), indicating that CM- β-CD was the better chiral NMR solvating agents for the recognition of the enantiomers of NA. Two dimensional rotating frame nuclear Overhauser enhancement spectroscopy (ROESY) experiments were also performed to explain the binding properties in terms of spatial fitting of the NA molecule into the macrocyclic cavities.
216 - 220
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