Carbohydrate receptors combining both a macrocyclic building block and flexible side arms as recognition units: design, syntheses, and binding studies.

Carbohydrate receptors combining a macrocyclic building block and two flexible side arms were designed on the base of the analysis of the binding motifs found in the crystal structures of the complexes formed between artificial receptors and monosaccharides, reported previously by our group. Binding studies in two-phase systems, such as extractions of sugars from water into organic phase, as well as in homogeneous organic media, using (1)H NMR and fluorescence spectroscopic titrations, confirmed the suitability of the designed compounds to act as highly effective and selective carbohydrate receptors. Depending on the nature of the bridges and side arms used as the building blocks, various receptors with different binding properties could be developed. The obtained results confirmed the validity of the receptor design and revealed that crystalline receptor-sugar complexes are particularly a valuable basis for the design of new effective receptor systems.