Oxime-Based Receptors for Mono- and Disaccharides

Representatives of a new series of acyclic oxime-based receptors were prepared and their binding properties
toward neutral sugar molecules studied. 1H NMR and fluorescence titrations revealed that receptors 2a
and 2b, incorporating suitable positioned amine and oxime moieties, are able to form strong 1:1 complexes
(Ka1 ∼ 105 M-1) with dodecyl α- and β-maltoside in chloroform solutions. Furthermore, the binding
studies with β-glucopyranoside indicated the formation of complexes with 1:1 and 1:2 receptor−monosaccharide binding stoichiometry (with overall binding constant β2 ∼ 105 M-2). Both hydrogen
bonding and interactions of the sugar CH's with the phenyl rings of the receptor contribute to the
stabilization of the receptor−sugar complexes. Molecular modeling calculations, synthesis, and binding
studies are described.