Glucopyranoside recognition by polypyridine-macrocyclic receptors possessing a wide cavity with a flexible linkage

New polypyridine-macrocyclic receptors for glucopyranosides were designed and synthesized. The artificial receptors possess a terpyridine skeleton as a hydrogen-bonding site and a flexible polyoxyethylene chain as a bridge for the macrocyclic structure, in which the cavity of the receptors is large enough to incorporate pyranosides. The receptors showed high affinities for n-octyl β-(D)-glucopyranoside, and selective binding of the receptors was observed between epimeric pyranosides. The results obtained in this paper demonstrated versatility of the terpyridine skeleton as a hydrogenbonding site for saccharides.