A molecular receptor for zwitterionic phenylalanine.

The combination of a 1,3-ketoenol system and two pyridine molecules attached as sulfonamide and carboxamide to a benzofuran skeleton allows the preparation of a novel chiral receptor for zwitterionic phenylalanine association. Interestingly, no crown-ether, urea or guanidinium are necessary to carry out the extraction of amino acids from the aqueous solution, which constitutes a breakthrough in comparison with other receptors for zwitterionic amino acid extraction.

A highly selective receptor for zwitterionic proline.

A chiral chromane receptor has been synthesized which mimics the oxyanion hole of the enzymes. In this receptor H-bonds and cation-π interactions team up to generate an apolar host-guest complex with zwitterionic proline. This complex allows the extraction of only proline to a chloroform phase, while no other natural amino acids are extracted.

Chiral recognition with a benzofuran receptor that mimics an oxyanion hole.

A new chiral benzofuran receptor has been synthesized and its properties in the association of amino acid derivatives have been studied. X-ray structures were obtained and these corroborate the presence of an oxyanion-hole motif in these structures.