1996 Fiscal Year Final Research Report Summary
Chiral recognition by novel host-guest complexation based on a combination of hydrophobic and electrostatic interactions in aqueous media
| Project/Area Number |
07672291
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Chemical pharmacy
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| Research Institution | Tokyo University of Pharmacy and Life Science |
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Principal Investigator |
DOBASHI Akira Tokyo University of Pharmacy and Life Science, School of Pharmacy, Professor, 薬学部, 教授 (40138962)
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| Co-Investigator(Kenkyū-buntansha) |
HAMADA Masaki Tokyo University of Pharmacy and Life Science, School of Pharmacy, Assistant Pro, 薬学部, 助手 (60246676)
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| Project Period (FY) |
1995 – 1996
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| Keywords | chiral recognition / enantiomer / amino acid / hydrophobicity / electrostatic force |
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| Research Abstract |
Our aim is to develop novel chiral host-guest complexation made up by hydrophobic and electrostatic interactions to discriminate enantiomers of aromatic amino acids. A chiral host comprised of two L-tyrosine residues and Diederich's bisphenol (4,4-bis (4-hydroxyphenyl) piperidine) can make a cyclic struucture with complementary electrostatic interactions between ammonium (NH_3^+) and carboxylate (COO^-) groups of the terminal tyrosine residues. This was found by conformational analysis of the host with molecular mechanics and molecular dynamics calculations. This cyclic host formed a dimer interlinked via their electrostatic forces in water and the dimerization equilibrirum constant estimated by NMR measurement was 170 (M^<-1>) at 25ﾟC.Fluorescence study using pyrene, dansylic acid (DNS) and 8-anilino-1-naphthalenesulfonic acid (ANS) showed that the dimeric host had a hydrophobic cavity to entrap these probes. Enantiomers of aromatic amino acids such as phenylalanine, tyrosine and tryptophan were discriminated with reversed phase chromatography using ODS packing coated by the chiral host. The L enantiomers were retained in greater extent than the D enantiomers in all amino acids resolved. The amino acid enantiomes should be bound to the dimeric host by inclusion of its aromatic side chains into the hydrophobic cavity and rearrangement of electrostatic networks between the four sets of NH_3^+ and COO^- groups.
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