Remarkably strong, uncharged hydrogen-bonding interactions of polypyridine-macrocyclic receptors for deoxyribofuranosides

Novel macrocyclic saccharide receptors that possess a pyridine-pyridone- pyridine arrangement as a hydrogen-bonding motif are presented. The artificial receptors exhibited a remarkably strong binding affinity for deoxyribofuranoside derivatives in CDCl₃ (K(a) = 19 000 M^-1; -ΔG₂₉₈ = 24.4 kJ/mol), one of the highest values of artificial receptors having only uncharged hydrogen-bonding sites for monosaccharide derivatives. Selective extraction of deoxyribose by the receptors was also observed; the extractabilities, or affinities to the receptors of various pentoses and hexoses, decreased in the following order: deoxyribose > lyxose ≃ ribose > arabinose ≃ fructose ≃ xylose > glucose > mannose > galactose.