Experimental support differenciating two proposed chiral recognition models for the resolution of N-(3,5-Dinitrobenzoyl)-α-arylalkylamines on high-performance liquid chromatography chiral stationary phases

Hyun, Myung Ho; Ryoo, Jae-Jeong; Pirkle, William H.

doi:10.1016/s0021-9673(00)00485-4

Cited by 22 publications

(11 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These This difference may be occasioned by additional edge-to-face pÀp interaction between H8 proton and the phenyl group at the chiral center. 19 From this result, it is possible to imagine that the phenyl group on chiral selector may be closely located above the H8 proton in order to affect the ring current effect.…”

Section: Resultsmentioning

confidence: 99%

NMR studies of chiral discrimination relevant to the enantioseparation of N‐acylarylalkylamines by an (R)‐phenylglycinol‐derived chiral selector

Im¹,

Ryoo

Lee

et al. 2002

Chirality

Self Cite

View full text Add to dashboard Cite

Recently, it was reported that the chiral recognition ability of (R)-N-3,5-dinitrobenzoyl phenylglycinol derivative was examined as a new HPLC chiral stationary phase (CSP 1) for the resolution of racemic N-acylnaphthylalkylamines. However, the mechanism of chiral discrimination on the CSP remained elusive until now. In this study, a spectroscopic investigation of the chiral discrimination mechanism of CSP 1 was undertaken using mixtures of (R)-N-3,5-dinitrobenzoyl phenylglycinol-derived chiral selector (2) and each of the enantiomers of N-acylnaphthylalkylamines (3) by NMR study. First, the differences in free energy changes (DeltaDeltaG) upon diastereomeric complexation in solution between the complex of each isomer with chiral selector 2 by NMR titration were calculated. The values were then compared with those estimated by chiral HPLC. The chemical shift changes of each proton on the chiral selector and analytes were also checked and it was found that the chemical shift changes decreased continuously as the acyl group on analytes increased in length. This observation was consistent with the HPLC data. From these experimental results, the interaction mechanism of chiral discrimination between the chiral selector and the analytes is more precisely explained.

show abstract

Section: Resultsmentioning

confidence: 99%

NMR studies of chiral discrimination relevant to the enantioseparation of N‐acylarylalkylamines by an (R)‐phenylglycinol‐derived chiral selector

Im¹,

Ryoo

Lee

et al. 2002

Chirality

Self Cite

View full text Add to dashboard Cite

show abstract

“…Chiral recognition, responsible for the formation of the new complexes, is a very well described process based on the 'three points interactions' concept. 13,16,18 The formation of these complexes, therefore, resulted from different interactions. Consequently, complexes with different stabilities (and life-times) are formed.…”

Section: Retentivity and Enantioselectivity Obtained For Racemates Usmentioning

confidence: 99%

“…[8][9][10][11][12][13][14][15][16][17][18] In HPLC this resolution is only possible by the transient formation of a pair of diastereomers with different chemical properties and consequently different retentivities. For this purpose enantiomers are submitted to chromatography either on a chiral stationary phase (CSP) or using an achiral stationary phase with a chiral modifier in the mobile phase.…”

Section: Introductionmentioning

confidence: 99%

Chiral Ligand Exchange Chromatography: Separation of Enantiomeric Mixtures of Underivatized α-Amino Acids under UV Detection

Nazareth¹,

Antunes²

2002

J. Braz. Chem. Soc.

View full text Add to dashboard Cite

) em água ou em água/ metanol. A utilização de água/metanol leva a uma grande diminuição dos tempos de retenção dos α-amino ácidos mais hidrofóbicos, preservando a separação enantiomérica. O pH precisa ser alto o bastante para permitir a presença de grupos -NH 2 livres, o que torna a complexação com Cu(II) mais fácil. α-Amino ácidos conformacionalmente mais restritos, como a L-prolina e a L-hidroxiprolina, conduziram a separações enantioméricas menores. A formação de complexos pseudo-homoquirais e pseudo-heteroquirais, por troca de ligantes, que é cinética e termodinamicamente controlada, desempenha um papel fundamental para a separação enantiomérica desejada. Esta metodologia simples e barata pode ser usada em qualquer laboratório envolvido em síntese de α-amino ácidos.Enantiomeric mixtures of alanine, serine, threonine, valine, methionine, leucine and norleucine were resolved in ligand exchange reversed phase HPLC (reproducibly), by using L-proline, L-) and Cu(CH 3 COO) 2 (1 mmol L -1 ) in water or in water/methanol. The latter mobile phase greatly decreased the retention time of the more hydrophobic α-amino acids, preserving enantioseparation. pH must be high enough to allow the presence of free -NH 2 groups in order to make the complexation with Cu(II) easier. The more restricted conformation of L-proline and L-hydroxyproline led to lower enantioseparations. The ligand exchange formation of pseudo-homochiral and pseudo-heterochiral complexes, thermodynamically and kinetically controlled, plays a fundamental role for the desired enantiomeric chromatographic separation. This simple and inexpensive methodology can be used routinely by any laboratory involved in α-amino acid synthesis.

show abstract

“…Importantly, at least one of the interactions must be stereochemically dependent when one of the enantiomers is separated. A simplified “single mechanism” model was later proposed by Hyun et al ., with the importance of face to edge π–π interaction between aromatic rings 9. It might imply that the π–π interaction could probably be predominant among various interactions for certain chiral separations.…”

Section: Introductionmentioning

confidence: 99%

Phenylcarbamoylated β‐CD: π‐Acidic and π‐basic chiral selectors for HPLC

Lin¹,

Luo²,

Zhang³

et al. 2010

J of Separation Science

View full text Add to dashboard Cite

Two types of chiral stationary phases for HPLC based on pi-acidic or pi-basic perphenylcarbamoylated beta-CDs were synthesized. The relative structural features of the two effective chiral selectors are discussed and compared in both normal-phase and RP modes. In addition, the nature and concentration of alcoholic modifiers were varied for optimal separation in normal phase and the structural variation of the analytes was also examined. The results showed that hydrogen bonding, steric effect and pi-acidic-pi-basic interaction contributed greatly to enantioseparation. Upon comparison, some of the differences in the separation behavior of the two types of chiral stationary phases might be due to the pi-acidic or pi-basic phenylcarbamate groups.

show abstract

Experimental support differenciating two proposed chiral recognition models for the resolution of N-(3,5-Dinitrobenzoyl)-α-arylalkylamines on high-performance liquid chromatography chiral stationary phases

Cited by 22 publications

References 19 publications

NMR studies of chiral discrimination relevant to the enantioseparation of N‐acylarylalkylamines by an (R)‐phenylglycinol‐derived chiral selector

NMR studies of chiral discrimination relevant to the enantioseparation of N‐acylarylalkylamines by an (R)‐phenylglycinol‐derived chiral selector

Chiral Ligand Exchange Chromatography: Separation of Enantiomeric Mixtures of Underivatized α-Amino Acids under UV Detection

Phenylcarbamoylated β‐CD: π‐Acidic and π‐basic chiral selectors for HPLC

Contact Info

Product

Resources

About