A simple model system for the study of carbohydrate--aromatic interactions.

Universita' di Milano, Dipartimento di Chimica Organica e Industriale e Centro di Eccellenza CISI, via Venezian 21, 20133 Milano, Italy.
Journal of the American Chemical Society (Impact Factor: 11.44). 04/2007; 129(10):2890-900. DOI: 10.1021/ja066633g
Source: PubMed

ABSTRACT A molecular scaffold was identified which enables the establishment of intramolecular interactions between a monosaccharide and a nearby phenyl ring. A group of molecules containing four different monosaccharides (glucose, galactose, N-acetyl-glucosamine, and N-acetyl-galactosamine) was synthesized and used to investigate the extent and nature of this carbohydrate-arene interaction, as well as the effect on the overall 3D structure of the molecules involved. The sugar-aromatic distance was evaluated by rigorous NMR studies supported by molecular modeling and found to be constant throughout the series, independent of the nature of the sugar and of the conformational behavior of the fragment connecting the two elements. Ab initio calculations at the B3LYP/DZV(2d,p) level of theory enable the analysis of the electronic nature of the interaction. The study shows that, given the opportunity, persistent intramolecular aromatic-sugar interactions can be established and can significantly influence overall molecular shape and energetics. These results have important implications in the design of structural mimics of oligosaccharides.

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