Evaluating Chiral Separation Interactions by Use of Diastereomeric Polymeric Dipeptide Surfactants

Billiot, Eugene; Thibodeaux, Stefan Jon; Shamsi, Shahab A.; Warner, Isiah M.

doi:10.1021/ac990540i

Cited by 54 publications

(53 citation statements)

References 30 publications

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“…A breakthrough in understanding the chiral interaction sites via CE was made when poly SULL was introduced (42). This dipeptide polymeric surfactant has two chiral centers that can be configured as D This elution order suggests that chiral discrimination for Alp and Prop occurs mainly at the C-terminal of dipeptide polymeric surfactants.…”

Section: A Ac Ch Hi Ir Ra Al L P Po Ol Ly Ym Me Er Rs Smentioning

confidence: 99%

Peer Reviewed: Molecular Micelles: Novel Pseudostationary Phases for CE

Shamsi¹,

Palmer²,

Warner³

2001

Anal. Chem.

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Section: A Ac Ch Hi Ir Ra Al L P Po Ol Ly Ym Me Er Rs Smentioning

confidence: 99%

Peer Reviewed: Molecular Micelles: Novel Pseudostationary Phases for CE

Shamsi¹,

Palmer²,

Warner³

2001

Anal. Chem.

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“…Since diastereomers can have different physical properties and different reactivities, the diastereomer type surfactant which is composed of an amino acid has greater research interest. However, there are few studies concerning the dipeptide type of surfactant composed of diastereomers 17,18) . In this study, the three isomers of N-dodecanoyl phenylalanyl-phenylalanine were chosen in order to examine the effect of the diastereomer on the aggregation behavior of the surfactant.…”

Section: Introductionmentioning

confidence: 99%

Effect of Stereochemistry on the Molecular Aggregation of Phenylalanine Dipeptide-type Surfactants

et al. 2008

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The aggregation behaviors of three stereoisomers of tetramethylammonium N-dodecanoyl phenylalanylphenylalaninate in dilute aqueous solution were investigated. From surface tension, fluorescence intensity using probes, and heat of dilution measurements, it was suggested that the critical aggregation concentration was the same between the enantiomers, but was obviously different between the diastereomers. It was also found that these surfactants formed large aggregates at lower concentrations. These large aggregates were then transformed to micelles at higher concentrations similarly to the potassium N-acyl phenylalaninate system. Furthermore, the fluorescence intensity of auramine increased strikingly in the N-dodecanoyl-L-phenylalanyl-L-phenylalanine (homo-chiral dipeptide-type surfactant) system. The fluorescence intensity of auramine in the aggregate of homo-chiral dipeptide-type surfactant was 20 times larger than that in the hetero-chiral dipeptide-type surfactant.

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“…1,2 Micelles formed spontaneously by ionic surfactants 3,4 and ionic micelle-like polymers [5][6][7][8] function as well as pseudostationary phases in EKC. The solute retentivity and separability in macromolecules may be explained as being due to the formation of hydrophobic interior regions and the solute distribution within these regions.…”

Section: Introductionmentioning

confidence: 99%

Chiral Separation by Electrokinetic Capillary Chromatography Using Newly Synthesized Linear Polymers Containing l-Amino Acid Moieties

Hamada

Dobashi

2002

ANAL. SCI.

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Electrokinetic capillary chromatography (EKC) is an advanced technique for determining whether ionic macromolecules, in which solutes are distributed from the bulk aqueous phase, undergo separation.1,2 Micelles formed spontaneously by ionic surfactants 3,4 and ionic micelle-like polymers 5-8 function as well as pseudostationary phases in EKC. The solute retentivity and separability in macromolecules may be explained as being due to the formation of hydrophobic interior regions and the solute distribution within these regions. [9][10][11] In the present study, chiral linear polymers derived from Nacryloyl-L-amino acid derivatives were found to aggregate in aqueous solution, and the polymers to enantioselectively take in racemic amino acid derivatives during the EKC separation process. Various chiral polymers have been prepared by the thermal telomerization of N-acryloyl-L-valine and N-acryloyl-Lalanine derivatives using 3-mercaptopropionic acid (3-MPA) as a radical transfer agent. 12 For two series of polymers, the derivatives used were methyl and tert-butyl esters to obtain carboxylic acid, which was subsequently cleaved, with Nmethylamide presumably remaining in the polymer. Amino acid residues of polymers are lined up repeatedly on straight carbon backbones formed by the polymerization of acryloyl groups, as is apparent from Fig. 1. The elongation of a monomer that determines the molecular weights of the resulting polymers was controlled by mixing the ratios of the amino acid derivatives to 3-MPA. Removal of the ester groups from both types of unimolecular polymers and copolymers rendered them water-soluble. Dissociation in the carboxylic acid present in the residues should change according to the pH of the migrating solution, and thus aggregation of the polymers that permits enantiomer absorption may be controlled by electric repulsion between these functional groups. The pH dependence is discussed based on the microscopic hydrophobicity, as assessed from the fluorescence of pyrene adsorbed onto the polymers in water. ExperimentalEKC was conducted using a Model 270A capillary electrophoresis system (PE Applied Biosystems, Tokyo, Japan). Chromatography was carried out at 25˚C using fused-silica tubing (50 µm i.d. × 70 cm, 50 cm effective length; PE Applied Biosystems). Methanol was used as the sample solvent, and the sample solution was injected hydrodynamically into a capillary over a period of 0.2 s. The polymer hydrophobicity was determined from the intensity ratio of the pyrene emission peak at 383 nm (I383) relative to that at 373 nm (I373) (I383/I373) in a 2.0 w/v% aqueous solution saturated with pyrene. Pyrene was excited at 337 nm and its fluorescence spectrum was measured with a fluorospectrophotometer (FP-777; JASCO, Tokyo, Japan) at 25˚C. 12 A 1 H-NMR measurement was made using a Varian Gemini-300 (300 MHz NMR). The internal standard was chloroform (7.26 ppm) in a deuteriochloroform solution. Preparation of N-acryloyl-L-alanine methyl ester (monomer 1), N-acryloyl-L-valine methyl ester (monomer 2a) ...

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Evaluating Chiral Separation Interactions by Use of Diastereomeric Polymeric Dipeptide Surfactants

Cited by 54 publications

References 30 publications

Peer Reviewed: Molecular Micelles: Novel Pseudostationary Phases for CE

Peer Reviewed: Molecular Micelles: Novel Pseudostationary Phases for CE

Effect of Stereochemistry on the Molecular Aggregation of Phenylalanine Dipeptide-type Surfactants

Chiral Separation by Electrokinetic Capillary Chromatography Using Newly Synthesized Linear Polymers Containing l-Amino Acid Moieties

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