Molecular amplification in a dynamic system by ammonium cations

Using hydrazone chemistry, a simple dynamic system of macrocyclic pseudo-peptides was prepared which contains a cyclic structure that resembles a known receptor for ammonium cations. A series of ammonium salts were tested as templates and the expected receptor was amplified in different degrees according to the template used. Competitive non-covalent interactions with a crown ether were used to demonstrate in situ that the templated system is still dynamic. Formation of host-guest complexes was proven by ESI-MS and H-1 ROESY experiments. Relative affinities of the various templates for the isolated receptor correlate well with the effect they produce on the library composition. (C) 2002 Elsevier Science Ltd. All rights reserved.