Cellulose Chemistry Meets Click Chemistry: Syntheses and Properties of Cellulose-Based Glycoclusters with High Structural Homogeneity

Abstract

β-1,4-Glucans having oligosaccharide appendages (O-/N-linked β-maltoside and O-/N-linked β-lactoside) at 6C positions of all repeating units can be readily prepared from cellulose through a two step strategy composed of: (1) regio-selective and quantitative bromination/azidation to afford 6-azido-6-deoxycellulose; and (2) the subsequent Cu+-catalyzed coupling with oligosaccharides having terminal alkyne. The resultant cellulose derivatives showed improved water solubility in comparison to native cellulose; they, however, bound to carbohydrate-binding proteins in a rather non-specific manner. Molecular dynamics calculations revealed that these properties are attributable to rigid sheet-like structures of the cellulose derivatives and the subsequent exposure of their hydrophobic moieties to solvents.