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Comparison of the chiral separation of amino‐acid derivatives by a teicoplanin and R N‐β‐CD CSPs using waterless mobile phases: Factors that enhance resolution
Author(s) -
Chen Shushi,
Ward Timothy
Publication year - 2004
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/chir.20035
Subject(s) - chemistry , teicoplanin , resolution (logic) , separation (statistics) , amino acid , combinatorial chemistry , stereochemistry , organic chemistry , chromatography , biochemistry , artificial intelligence , vancomycin , biology , bacteria , genetics , staphylococcus aureus , machine learning , computer science
Abstract A variety of compounds containing amines (i.e., amino acids, amino alcohols, etc.) were chemically derivatized with a variety of electrophilic tagging reagents to elucidate the chiral recognition sites on a teicoplanin‐bonded chiral stationary phase (CSP) and on R ‐naphthylethylcarbamate‐β‐cyclodextrin ( R N‐β‐CD)‐bonded CSP. Solutes were separated under optimum chromatographic conditions on teicoplanin and R N‐β‐CD CSPs for comparison using an acetonitrile‐based mobile phase. It was noted that the size of the analyte or tagging reagent exerted a greater influence on compounds separated on teicoplanin than on R N‐β‐CD when using the polar organic mode. This suggests that chiral recognition on teicoplanin CSP is more sensitive to size and indicates that the hydrophobic pocket of teicoplanin plays a significant role in chiral recognition in this mode. However, the type of functional groups had a greater impact than the size of analyte on separations obtained from R N‐β‐CD phase in the polar‐organic mode. Specifically, the π–π interaction was enhanced by derivatizing the aromatic ring of the tagging reagent with electron‐withdrawing groups and thus altered the resolution substantially. For both phases, chiral recognition is most pronounced when the stereogenic center of the analyte is near the tagging moiety and surrounded by functional groups (e.g., carboxylic, etc.) which are favorable for hydrogen bonding. Chirality 16:318–330, 2004. © 2004 Wiley‐Liss, Inc.