ISSN:
0899-0042
Keywords:
enantioselective transport
;
single two-phase liquid-liquid extraction
;
N-protected α-amino acid derivatives
;
quinine carbamate-type chiral selectors
;
chiral anion-exchange carrier
;
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Two-phase liquid-liquid extraction experiments were undertaken to study the enantioselective transport of the chiral N-protected α-amino acid derivatives from an aqueous buffer solution into an organic phase employing highly lipophilic carbamoylated quinine as chiral selector and phase transfer carrier, respectively. The chiral separation, derived from enantioselective ion-pair formation and differential solubility in the aqueous and organic phases of diastereomeric associates thus formed has been shown to be primarily dependent on the structure of the selectand, the nature of the organic solvent, the molar ratio of a given chiral selector to selectand in the two phases, and the pH of the aqueous phase. Extracted enantiomers were recovered by back-extraction using a relatively polar acidic medium in which the selector is barely insoluble. Thus, the enantiomeric purity of N-(3,5-dinitrobenzoyl)-leucine exceeded 95% enantiomeric excess with 70% overall yield with a single extraction and back-extraction step. Chirality 9:268-273, 1997. © 1997 Wiley-Liss, Inc.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
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