Membrane extraction of organic compounds 3. A new receptor fragment for carboxylate groups based of the calix[4]arene platform

Abstract

A new type of macrocyclic receptor able to bind organic substrates containing carboxy and carboxylate groups was designed on the basis of 1,3-disubstituted calix[4]arenes. A series of disubstitited calix[4]arenes were prepared in 60-80% yields by selective 1,3-alkylation of p-tert-butylcalix[4]arene. The compounds obtained were tested as carriers for DL-tartaric, glycolic, DL-amygdalic, and DL-glutamic acids through liquid membranes immobilized on a polymer matrix. The structural factors favorable for the transport of these hydrophilic substrates through lipophilic membranes were established.