Synthesis and molecular recognition of novel receptor for amino acid zwitterions

A novel artificial receptor 1 for aromatic amino acid zwitterions was prepa red in three steps from the chiral bis(aminomethyl) bicyclic guanidinium sa lt. The bicyclic guanidinium group is covalently connected with an azacrown ether and three naphthylmethyl group by means of chemically stable amide a nd imino bonds. The experiments of the competition extraction and H-1 NMR i ndicated that the receptor selectively binds to L - aromatic amino acid zwi tterions and can transfer it from water into dichloromethane.