Chiral recognition of verapamil by cyclodextrins studied with capillary electrophoresis, NMR spectroscopy, and electrospray ionization mass spectrometry

Chankvetadze, Bezhan; Burjanadze, Naira; Pintore, Giorgio Antonio Mario; Strickmann, Dirk B; Bergenthal, Dieter; Blaschke, Gottfried

doi:10.1002/(sici)1520-636x(1999)11:8<635::aid-chir5>3.0.co;2-d

Cited by 68 publications

(28 citation statements)

References 41 publications

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“…As it can be seen from this table, a 2,6-di-O-methylation affects the enantiomer affinity pattern in rather few cases compared to 2,3,6-tri-O-methylation. The possible mechanisms of the reversal of enantiomer affinity pattern of some chiral analytes to the native b-CD and TM-b-CD are discussed in several articles [8,18,19]. …”

Section: Reversal Of the Enantiomer Affinity Pattern Depending On Thementioning

confidence: 99%

Enantiomer migration order in chiral capillary electrophoresis

2002

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Enantiomer migration order (EMO) in chiral capillary electrophoresis (CE) represents a challenging issue, referred to in less than 20% of the articles on CE enantioseparations. This review article will (i) illustrate the actuality of the topic, (ii) discuss some technical problems related to EMO in CE enantioseparations, (iii) examine the principal differences between CE and other separation techniques from the viewpoint of enantiomer elution order, (iv) demonstrate the potential for a designed reversal of EMO in CE, and (v) emphasize the importance of studying EMO for better understanding of chiral CE as well as its more effective application. Along with CE, the results obtained by other instrumental techniques such as nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry (MS), X-ray crystallography, as well as molecular modeling calculations will be shortly discussed. Rather than referring to all published examples of the opposite migration order of enantiomers in CE, the emphasis will be on general aspects. Recently, the reversal of the EMO was described in detail in a book chapter (Chankvetadze, B., Capillary Electrophoresis in Chiral Analysis, Wiley & Sons, Chichester, UK 1997, Chapter 12) as well as in three review articles.

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Section: Reversal Of the Enantiomer Affinity Pattern Depending On Thementioning

confidence: 99%

Enantiomer migration order in chiral capillary electrophoresis

2002

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“…Thus, for example, the enantiomers of AGT exhibit the same affinity pattern towards native a-and g-CD, but an opposite one towards b-CD [26]. The enantiomers of ChPh [27], BrPh [28], DIM [29], and VP [30] The correct understanding of the underlying nuances of the affinity reversal of enantiomers towards CDs having different cavity size and/or carrying different substituents may provide a key for the elucidation of binding and chiral recognition mechanisms by these widely used macrocyclic hosts. It must be noted that based on our experience the structural reasons leading to a dramatic change of the affinity pattern may be minor and not straightforward.…”

Section: Enantioseparation With â-Cd and Hmdisu-â-cdmentioning

confidence: 99%

Comparative enantioseparations with native β-cyclodextrin and heptakis-(2-O-methyl- 3,6-di-O-sulfo)-β-cyclodextrin in capillary electrophoresis

et al. 2002

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Twenty-three cationic chiral analytes were resolved in capillary electrophoresis using native beta-cyclodextrin and single isomer heptakis-(2-O-methyl-3,6-di-O-sulfo)-beta-cyclodextrin as chiral selectors. For 12 of 16 chiral analytes resolved with both chiral selectors the enantiomer migration order was opposite. In selected cases the structure of cyclodextrin-analyte complexes in aqueous solution was investigated using one-dimensional transverse rotating frame nuclear Overhauser and exchange spectroscopy. It was found that in contrast to mainly inclusion-type complexes between chiral analytes and beta-cyclodextrin, external complexes are formed between the chiral analytes and structurally crowded, highly charged heptakis-(2-O-methyl-3,6-di-O-sulfo)-beta-cyclodextrin.

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“…The stoichiometry and association/binding constant of the host-guest complex can be readily obtained from NMR titration data [17][18][19]. 1 H NMR spectra of mixture of CD and guest molecule are recorded and changes in the chemical shift of both host and guest are studied.…”

Section: Introductionmentioning

confidence: 99%