Chiral discrimination by NMR spectroscopy of ephedrine and N-methylephedrine induced by ?-cyclodextrin, heptakis(2,3-di-O-acetyl)?-cyclodextrin, and heptakis (6-O-acetyl)?-cyclodextrin

Holzgrabe, Ulrike; Mallwitz, Henning; Branch, Sarah K.; Jefferies, T.M.; Wiese, M. V.

doi:10.1002/(sici)1520-636x(1997)9:3<211::aid-chir2>3.0.co;2-i

Cited by 41 publications

(22 citation statements)

References 17 publications

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“…In the case of SBE-β-CD, all four protons of [Ru(phen) 3 ] 2+ provide split signals, while signals for three of the protons are separated into a pair of peaks for the other four derivatized cyclodextrins. Many NMR studies of chiral selectors have shown that protons closer to the binding site show greater enantiomeric differences in their CISs [36, 41, 44]. It should be noted that the singlet signal (H4) of [Ru(phen) 3 ] 2+ was split by five different derivatized cyclodextrins, and it is the only proton signal that splits in all cases.…”

Section: Resultsmentioning

confidence: 99%

Enantioselective host–guest complexation of Ru(II) trisdiimine complexes using neutral and anionic derivatized cyclodextrins

MacDonnell

Armstrong

2009

Inorganica Chimica Acta

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Enantioselective host-guest complexation between five racemic Ru(II) trisdiimine complexes and eight derivatized cyclodextrins (CDs) has been examined by NMR techniques. The appearance of non-equivalent complexation-induced shifts of between the Δ and Λ-enantionomers of the Ru(II) trisdiimine complexes and derivatized CDs is readily observed by NMR. In particular, sulfobutyl ether-β-cyclodextrin sodium salt (SBE-β-CD), R-naphtylethyl carbamate β-cyclodextrin (RN-β-CD), and S-naphtylethyl carbamate β-cyclodextrin (SN-β-CD) showed good enantiodiscrimination for all five Ru complexes examined, which indicates that aromatic and anionic derivatizing groups are beneficial for chiral recognition. The complexation stoichiometry between SBE-β-CD and [Ru(phen)3]2+ was found to be 1: 1 and binding constants reveal that Λ-[Ru(phen)3]2+ binds more strongly to SBE-β-CD than the Δ-enantiomer. Correlations between this NMR method and separative techniques based on CDs as chiral discriminating agents (i.e., selectors) are discussed in detail.

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Section: Resultsmentioning

confidence: 99%

Enantioselective host–guest complexation of Ru(II) trisdiimine complexes using neutral and anionic derivatized cyclodextrins

MacDonnell

Armstrong

2009

Inorganica Chimica Acta

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“…In contrast, the pattern obtained for the acetylated CDs, DIAC-b-CD and HDAS-b-CD, did not provide substantial information on the complexation because the hydrogens are more or less randomly shifted. This is in accordance with results obtained for both CDs with phenethylamines [10,11,25]. However, comparing the patterns of the CICS of the acetylated CDs for the enantiomers of the dipeptides the Dd values for the corresponding diastereomeric complexes are rather different indicating the ability of the acetylated CDs to discriminate between the enantiomers.…”

Section: Changes Of the Chemicals Shifts Of The Cdsmentioning

confidence: 99%

Studies on the chiral recognition of peptide enantiomers by neutral and sulfated β-cyclodextrin and heptakis-(2,3-di-O-acetyl)-β-cyclodextrin using capillary electrophoresis and nuclear magnetic resonance

Süß¹,

Kahle

Holzgrabe

et al. 2002

Electrophoresis

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The separation of dipeptide and tripeptide enantiomers using a neutral single isomer cyclodextrin (CD) derivative, heptakis-(2,3-di-O-acetyl)-beta-CD (DIAC-beta-CD), was investigated with respect to the amino acid sequence applying standard separation conditions. With only one exception the DD-enantiomers migrated faster than the LL-stereoisomers. Separations obtained for the same set of peptides using beta-CD and the sulfated single isomer derivatives heptakis-(2,3-di-O-acetyl-6-sulfo)-beta-CD (HDAS-beta-CD) and heptakis-6-sulfo-beta-CD (HS-beta-CD) revealed identical enantiomer migration order in the presence of the 2,3-disubstituted derivatives DIAC-beta-CD and HDAS-beta-CD. In contrast, reversed migration sequence was found for beta-CD and HS-beta-CD compared to DIAC-beta CD and HDAS-beta-CD indicating the importance of the substitution pattern on the wider rim of the CD cavity on the chiral recognition of the peptide enantiomers by the CDs. Nuclear magnetic resonance (NMR) experiments indicated different complexation modes between the enantiomers and the CDs depending on the presence of acetyl substituents on the wider rim of the CD torus. Thus, the CD-induced chemical shifts observed in samples containing Ala-Phe or Ala-Tyr and beta-CD or HS-beta-CD were consistent with an inclusion of the aromatic moiety into the CD cavity. Although the CD-induced chemical shifts in the presence of DIAC-beta-CD and HDAS-beta-CD did not allow direct conclusions on the complexation mode they substantially differed from those observed in the presence of 2,3-unsubstituted CDs indicating different structures of the peptide-CD complexes.

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“…Hence they can be found as impurities in this stimulant . The enantioseparation of these compounds has been studied by different groups . Nevertheless, to the best of our knowledge, the determination of binding constants between phenethylamines and cyclodextrins has only been reported for (2,6‐di‐O‐methyl)‐β‐cyclodextrin complexes .…”

Section: Introductionmentioning

confidence: 99%

Characterization of complexes between phenethylamine enantiomers and β‐cyclodextrin derivatives by capillary electrophoresis—Determination of binding constants and complex mobilities

et al. 2017

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To optimize chiral separation conditions and to improve the knowledge of enantioseparation, it is important to know the binding constants K between analytes and cyclodextrins and the electrophoretic mobilities of the temporarily formed analyte-cyclodextrin-complexes. K values for complexes between eight phenethylamine enantiomers, namely ephedrine, pseudoephedrine, methylephedrine and norephedrine, and four different β-cyclodextrin derivatives were determined by affinity capillary electrophoresis. The binding constants were calculated from the electrophoretic mobility values of the phenethylamine enantiomers at increasing concentrations of cyclodextrins in running buffer. Three different linear plotting methods (x-reciprocal, y-reciprocal, double reciprocal) and nonlinear regression were used for the determination of binding constants with β-cyclodextrin, (2-hydroxypropyl)-β-cyclodextrin, methyl-β-cyclodextrin and 6-O-α-maltosyl-β-cyclodextrin. The cyclodextrin concentration in a 50 mM phosphate buffer pH 3.0 was varied from 0 to 12 mM. To investigate the influence of the binding constant values on the enantioseparation the observed electrophoretic selectivities were compared with the obtained K values and the calculated enantiomer-cyclodextrin-complex mobilities. The different electrophoretic mobilities of the temporarily formed complexes were crucial factors for the migration order and enantioseparation of ephedrine derivatives. To verify the apparent binding constants determined by capillary electrophoresis, a titration process using ephedrine enantiomers and β-cyclodextrin was carried out. Furthermore, the isothermal titration calorimetry measurements gave information about the thermal properties of the complexes.

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Chiral discrimination by NMR spectroscopy of ephedrine and N-methylephedrine induced by ?-cyclodextrin, heptakis(2,3-di-O-acetyl)?-cyclodextrin, and heptakis (6-O-acetyl)?-cyclodextrin

Cited by 41 publications

References 17 publications

Enantioselective host–guest complexation of Ru(II) trisdiimine complexes using neutral and anionic derivatized cyclodextrins

Enantioselective host–guest complexation of Ru(II) trisdiimine complexes using neutral and anionic derivatized cyclodextrins

Studies on the chiral recognition of peptide enantiomers by neutral and sulfated β-cyclodextrin and heptakis-(2,3-di-O-acetyl)-β-cyclodextrin using capillary electrophoresis and nuclear magnetic resonance

Characterization of complexes between phenethylamine enantiomers and β‐cyclodextrin derivatives by capillary electrophoresis—Determination of binding constants and complex mobilities

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