There is a considerable interest in small molecules with receptor-like ion-binding properties.In 2006 Tajc and Miller created a new pH-switchable molecule by coupling tyrosine and cyelohexane 1,3,5-trimethanol which can serve as chelate-forming pH-switchable receptor either for various anions (e.g.Cl-,Br-) and cations (e.g.Ce4+,Ag+,Sn2+) in aqueous solution at high pH [1].Their work also indicated that the compound exists in two conformational states:in an extended conformation at low pH,whereas it appears in closed form in basic solutions.Metal-and anion-complex formations have been qualitatively studied in basic solutions with Zn2+,Cd2+ and halide ions.It has been reported that the anion complexation was an entropy-driven process and they observed neither anion-nor cation-binding at low pH.Of these observations the nonexistence of the anion-binding at low pH especially needs reinvestigation.On these principles we synthesized further mono-,di-,and trisubstituted derivatives in the ester bond with other amino acids (histidine,tryptophane,phenylalanine,and 4-amino-phenylalanine).