Alkyl β-d-cellulosides: non-reducing cellulose mimics

Abstract

Non-reducing cellulose mimics, termed alkyl β-d-cellulosides, were successfully prepared by two efficient multi-step syntheses starting from commercially available microcrystalline cellulose or cellulose triacetate. Introduction of the alkoxy moiety and degradation of the cellulose backbone was carried out in the presence of a Lewis acid, on one hand. On the other hand, cellulose hydrolysis mediated by mineral acids was combined with β-glycosidation performed in the presence of silver salts. The samples obtained possess a number-average degree of polymerization from 5 to 25, determined by size-exclusion chromatography, elemental analyses, NMR spectroscopy, and MALDI-TOF mass spectrometry. Samples in multi-gram quantities were available. Selective formation of a β-glycosidic bond between the C-1 atom of the reducing end group and alkoxy moieties was confirmed by a combination of 2D NMR spectroscopic and MALDI-TOF MS techniques. Due to the blocking of the aldehyde function, the cellulosides described are very useful mimics for the investigation of polysaccharide interactions with other complex molecules such as proteins or to determine polymer properties in solution or in solid state.