Synthesis of N-substituted cyclic triglycines and their response to metal ions

N,N′,N″-Trisubstituted-cyclo-triglycines were synthesized. The major conformation of these compounds has C3 symmetry, and the carbonyl groups and substituents on the nitrogen are inclined in the same direction. Their response to various metal ions was estimated by constructing ion-selective electrodes. Two of them responded selectively to Ca2+ over other cations, demonstrating that N,N′,N″-trisubstituted-cyclo-triglycines provide a new scaffold to act as host molecules.