Chiral alpha,omega-diesters react under high-pressure conditions (10 kbar) with alpha,omega-diamines to give chiral cyclic tetraamides Of C-2-symmetry. The complexation properties of tetraamides towards alkali metal cations (Li+, Na+, K+, Rb+ and Cs+) were estimated on the basis of ESI-MS spectra. (C) 2003 Elsevier Science Ltd. All rights reserved.
A New Approach to the Synthesis of Chiral Tetraazacoronands Derived from L-Alanine