Enantioselective transport of D,L-phenylalanine and D,L-phenylglycine through a bulk liquid membrane containing cinchona alkaloid derivatives as chiral selectors

Abstract

Diversos derivados de Cinchona foram testados como carregadores quirais móveis, para o transporte enantiosseletivo de D,L-fenilglicina e D,L-fenilalanina, através de uma membrana líquida orgânica volumosa (MLV). Os efeitos de vários parâmetros, como natureza do carregador, concentrações do solvente na membrana, do tampão, do soluto e do carregador, no enriquecimento quiral da MLV, foram avaliados. Somente a D,L-fenilglicina foi sujeita, em certo grau, ao transporte enantiosseletivo; a razão máxima de enantiosseletividade (as taxas de transporte iniciais do enantiômero L relativo ao antípoda) foi obtida empregando brometo de O-alil-N-(9-antracenilmetil) cinchonidínio como carregador. Em todos os casos, a seletividade mais alta foi observada durante os estágios iniciais do processo, indicando a taxa de aminoácido liberada da fase fonte (FF) para a fase orgânica da membrana (FM), como fator dirigente. O enriquecimento quiral pareceu depender mais de fatores termodinâmicos do que dos cinéticos, uma vez que a formação do complexo foi observada na interface (FF)/FM), enquanto a decomposição do complexo foi evidenciada na interface (FR)/(FM), onde FR é a fase receptora. O último fenômeno foi promovido pela presença de íons H + na FR. Different cinchona derivatives were tested as chiral mobile carriers for enantioselective transport of D,L-phenylglycine and D,L-phenylalanine through a bulk organic liquid membrane (BLM).The effects of several parameters such as carrier nature, membrane solvent, buffer, solute and carrier concentrations on BLM enrichment were evaluated. Only D,L-phenylglycine is subjected to enantioselective transport at a certain degree; the maximum enantioselectivity ratio (the initial transport rates of the L-enantiomer relative to the antipode) was reached by employing O-allyl-N-(9-anthracenylmethyl)cinchonidinium bromide as carrier. In all cases the highest selectivity was observed during the initial stages of the process, indicating the rate of amino acid release from the source phase (SP) to the membrane organic phase (MP) as the driving factor. Chiral enrichment appeared to depend on thermodynamic factors more than on kinetic ones, since the complex formation was observed at (SP)/MP) interface, while complex decomposition was evidenced at (RP)/(MP) interface, where RP is receiving phase. The last phenomenon was promoted by H + ions present in the RP.

Polymeric pseudo-liquid membranes from poly(dodecyl methacrylate): KCl transport and optical resolution

“…51 Cinchona alkaloid was also used as a transporter for optical resolution. 52 On the basis of these studies, AAMC was chosen as a transporter for enantioselective transport, and the membrane performance was investigated using a racemic mixture of Phegly as a model racemate.…”

Open-tubular Electrochromatographic Chiral Separation of Amino Acids Using an Organic Nanocrystals Immobilized Capillary

“…It has been reported that the ion pairing between positively-charged tertiary amine moiety in the quinuclidine ring of CCND and negatively-charged carboxylate group in the amino acids and the π-π interaction between the quinoline ring of CCND and the phenyl ring of DL-Phe plays a crucial role in the chiral selectivity of the cinchona alkaloids-based chiral column. 26,27 In the present condition, the best ion pairing and the π-π interaction would be attained at pH 5.0.…”

Polymeric Pseudo-Liquid Membranes from Poly(N-oleylacrylamide)

“…Cinchona alkaloid was also used as a transporter for optical resolution [55]. Based on those studies described above, AAMC was chosen as a transporter for enantioselective transport.…”