Membrane Transport of the Zwitterionic Aromatic α-Amino Acids by α-Aminophosphonates

Abstract

Bghly selective biological transport of amino acids is usually mediated by carrier proteins. The application of such membrane systems for the analysis and separation of amino acids has long studied. This work is devoted to the transport of zwitterionic form of aromatic a-amino acids such as d,l-Phe, d,l-DOPA, d,l-His, d,l-Tyr, d,l-Trp, via supported liquid membrane (SLM). The lipophilic α-aminophosphonates (I).

R₁ amyl or 2-ethylhexyl; R₂, R₂-(CH₂)4-(CH₂)5-CH₃ & (CH₃), C₄ H(CH₉) & H; H & H; have been used as carrier in the membrane systems composed of a porous polymeric support (Millipore Type FA) impregnated with 10^?1 M carrier in o-nitrophenyl n-octyl ether (amino acid concentration in source phase is 10^?3 M). The cell for membrane extractions is presented on Fig I.     

Membrane transport of dicarboxylic and α-hydroxy carboxylic acids induced by α-amino phosphonates

New -amino phosphonates containing different alkyl and aryl substituents at the -carbon atom were synthesized in high yields by the Kabachnik—Fields and Pudovik reactions. These compounds were studied as carriers of several -hydroxy carboxylic and dicarboxylic acids through liquid impregnated membranes. These -amino phosphonates studied are capable of molecular recognition of oxalic acid among structurally similar -hydroxy carboxylic and dicarboxylic acids. The efficiency and selectivity of mass transfer of oxalic acid increase with an increase in the lipophilicity of the -amino phosphonate.