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Titolo:
Chiral recognition of (18-crown-6)-tetracarboxylic acid as a chiral selector determined by NMR spectroscopy
Autore:
Bang, EJ; Jung, JW; Lee, WJ; Lee, DW; Lee, WT;
Indirizzi:
Chosun Univ, Coll Pharm, Kwangju 501709, South Korea Chosun Univ KwangjuSouth Korea 501709 harm, Kwangju 501709, South Korea Yonsei Univ, Dept Chem, Seoul 120749, South Korea Yonsei Univ Seoul South Korea 120749 ept Chem, Seoul 120749, South Korea Korea Basic Sci Inst, Seoul Branch, Seoul 136701, South Korea Korea Basic Sci Inst Seoul South Korea 136701 Seoul 136701, South Korea Yonsei Univ, Dept Biochem, Seoul 120749, South Korea Yonsei Univ Seoul South Korea 120749 Biochem, Seoul 120749, South Korea
Titolo Testata:
JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 2
fascicolo: 9, , anno: 2001,
pagine: 1685 - 1692
SICI:
1472-779X(200109):9<1685:CRO(AA>2.0.ZU;2-W
Fonte:
ISI
Lingua:
ENG
Soggetto:
LIQUID-CHROMATOGRAPHIC RESOLUTION; CAPILLARY ZONE ELECTROPHORESIS; RACEMIC AMINO-ACIDS; ACTIVE CROWN-ETHER; STATIONARY-PHASE; 18-CROWN-6-TETRACARBOXYLIC ACID; ENANTIOMER SEPARATION; MOLECULAR RECOGNITION; TETRACARBOXYLIC ACID; COMPLEXES;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
46
Recensione:
Indirizzi per estratti:
Indirizzo: Lee, WJ Chosun Univ, Coll Pharm, Kwangju 501709, South Korea Chosun Univ Kwangju South Korea 501709 angju 501709, South Korea
Citazione:
E.J. Bang et al., "Chiral recognition of (18-crown-6)-tetracarboxylic acid as a chiral selector determined by NMR spectroscopy", J CHEM S P2, (9), 2001, pp. 1685-1692

Abstract

It is shown that the chiral selector (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid (18-C-6-TA) employed for resolution of alpha -amino acids in capillary electrophoresis and in chiral HPLC can be used for resolution of alpha -amino acids and ester derivatives in NMR experiments. In a quest for the origin of chiral recognition of a-amino acids in the presence of 18-C-6-TA as a chiral selector, these interactions responsible for the differentialaffinities shown toward enantiomers are investigated by NMR spectroscopy. Chemical-shift differences of the corresponding H-1 and C-13 resonances of D- and L-phenylglycine (PG) or phenylglycine methyl ester (PG-ME) show thatmost chemical shifts in the presence of 18-C-6-TA moved in the same direction (i.e., upfield or downfield) as compared with those of the free state. Significant reduction of the T-1-values is observed for the host-guest complex molecules, indicating that the mobility of the isomers is significantlyreduced due to tight binding with 18-C-6-TA. NMR line broadening of the analyte upon complexation further supports this finding. The observed intermolecular NOES of the alpha -proton and ortho phenyl protons of PG or PG-ME in the presence of 18-C-6-TA are used for generating structures for 18-C-6-TA/enantiomer complexes. Molecular dynamics calculations based on NOEs illustrate the essential features of the chiral recognition mechanism: 1) three NH . . .O hydrogen bonds in a tripod arrangement between polyether oxygensof 18-C-6-TA and the ammonium moiety of the enantiomer; 2) a hydrophobic interaction between the polyether ring of 18-C-6-TA and the phenyl moiety ofthe enantiomer; 3) hydrogen bonding between the carboxylic acid of 18-C-6-TA and the carbonyl oxygen of the D-enantiomer.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 08/04/20 alle ore 23:48:09