Molecular recognition studies on naphthyridine derivatives.

The association constants Kb of three hosts I-III designed to have both enhanced hydrogen bonding donor strength and conformational preorganization with biotin analogues 1-5 are reported. 1H-NMR titrations under two different concentration conditions have been employed to determine the association constants Kb. A statistical analysis using a presence absence matrix has been applied to calculate the different contributions. Hydrogen bond interactions make naphthyridine derivatives II and III potent binders and effective receptors for (+)-biotin methyl ester (1), due to the complex stabilization by additional hydrogen bonds.