Hydrogen Bonding and Molecular Recognition: Synthetic, Complexation, and Structural Studies on Barbiturate Binding to an Artificial Receptor

Abstract

A series of synthetic receptors with strong selectivity for the barbiturate family of drugs has been prepared. The receptor design is based on two 2,6-diaminopyridine groups linked through an isophthalic acid spacer. X-ray crystallographic, H-1 NMR spectroscopic, and substrate binding studies confirm that six hydrogen bonds are formed between the receptor and its substrate. The strongest binding (K(a) almost-equal-to 10(5) M-1) is seen to those substrates containing the complementary barbituric acid core. Systematic deletion of hydrogen-bonding sites from the receptor and substrate allows an assessment of the contribution of individual binding sites to complexation.