Highlighting the possible secondary interactions in the role of balhimycin and its analogues for enantiorecognition in capillary electrophoresis

TY - JOUR

T1 - Highlighting the possible secondary interactions in the role of balhimycin and its analogues for enantiorecognition in capillary electrophoresis

AU - Jiang, Zhengjin

AU - Yang, Zhuohong

AU - Suessmuth, Roderich D.

AU - Smith, Norman Williams

AU - Lai, Shuting

PY - 2010/2/12

Y1 - 2010/2/12

N2 - It is believed that the enantiorecognition mechanism based on macrocyclic antibiotics involves multi-modal interactions via hydrogen bonding. pi-pi interaction, steric hindrance, hydrophobic interaction and so on. A variety of enantiomeric N-benzoylated amino acids were separated using balhimycin (A) or its analogues bromobalhimycin (B) and dechlorobalhimycin (C) as chiral mobile phase additive using a CE method, which combined the partial filling technique with the dynamic coating technique and the co-EOF electrophoresis technique. The enantioresolution and the migration time were highly relevant to the structure of analytes, especially to the substitutions on the N-tagged benzoyl moiety of the amino acids. A steric effect and pi-pi interaction based mechanism is proposed in order to explain some observed enantioresolution differences between positional isomers. Notably dechlorobalhimycin exhibited the best enantioresolution for several N-benzoylated derivatives of leucine, which was rarely observed for N-dansylated amino acid derivatives. The hydrophobicity difference of the aglycone pocket among three chiral selectors was assumed to account for this behaviour. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.

AB - It is believed that the enantiorecognition mechanism based on macrocyclic antibiotics involves multi-modal interactions via hydrogen bonding. pi-pi interaction, steric hindrance, hydrophobic interaction and so on. A variety of enantiomeric N-benzoylated amino acids were separated using balhimycin (A) or its analogues bromobalhimycin (B) and dechlorobalhimycin (C) as chiral mobile phase additive using a CE method, which combined the partial filling technique with the dynamic coating technique and the co-EOF electrophoresis technique. The enantioresolution and the migration time were highly relevant to the structure of analytes, especially to the substitutions on the N-tagged benzoyl moiety of the amino acids. A steric effect and pi-pi interaction based mechanism is proposed in order to explain some observed enantioresolution differences between positional isomers. Notably dechlorobalhimycin exhibited the best enantioresolution for several N-benzoylated derivatives of leucine, which was rarely observed for N-dansylated amino acid derivatives. The hydrophobicity difference of the aglycone pocket among three chiral selectors was assumed to account for this behaviour. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.

U2 - 10.1016/j.chroma.2009.09.035

DO - 10.1016/j.chroma.2009.09.035

M3 - Article

VL - 1217

SP - 1149

EP - 1156

JO - Journal of Chromatography A

JF - Journal of Chromatography A

IS - 7

ER -