Thiouroninm-thymine conjugate as a new carrier for selective transport of 5′-AMP

Extraction and transport behaviors of the new 5'-AMP receptors which have thiouronium group and which have both thiouronium and thymine group were investigated. As expected, the sequence of transport rate was 1 > 3 similar to 2 > 4. 1 showed the best transport ability, since it has both concave bis(thiouronium) binding site which can chelate phospate anion and covalently linked bis(thymine) moiety which can interact with adenine in 5'-AMP by hydrogen bonding involving both Watson-Crick and Hoogsteen recognition patterns. The less transport ability of 2 and 4 was assumed to be the result of disadvantage in complexation process entropically and enthalpically. The control experiment clearly showed that selective base-pairing contributed to increased transport. (C) 1998 Elsevier Science Ltd. All rights reserved.