All Sugar Based Cellulose Derivatives Synthesized by Azide–Alkyne Click Chemistry

• Published in: Macromolecular chemistry and physics 2020-01, Vol.221 (1), p.n/a
• Main Authors: Koschella, Andreas, Chien, Chih‐Ying, Iwata, Tadahisa, Thonhofer, Martin S., Wrodnigg, Tanja M., Heinze, Thomas
• Format: Article
• Language: English
• Subjects: 5‐azido‐5‐deoxy aldoses; Alkynes; azide–alkyne click chemistry; Cellulose; Chemical synthesis; Dimethyl sulfoxide; Monosaccharides; NMR spectroscopy; Organic chemistry; Polymers; solubility; structure–property relationships; sugar functionalized cellulose; Triazoles
• ISSN: 1022-1352; 1521-3935
• DOI: 10.1002/macp.201900343

Cellulose is functionalized with different monosaccharides by the azide–alkyne click chemistry approach. Either azide or alkyne moieties are attached to the cellulose backbone and allowed to react with sugar moieties bearing the opposite clickable groups. Between 16% and 100% of the reactive sites at the polymer can be functionalized with sugar molecules and a clear correlation between steric demand and DSSugar is observed. The polymers remain soluble in aprotic dipolar media like dimethyl sulfoxide. Products with a sufficient hydrophilicity dissolve in water as well. FTIR‐ and NMR spectroscopy reveal the triazole formation and indicate an incomplete conversion of the reactive sites as usually observed in the field of click chemistry with polymers. Copper‐catalyzed azide–alkyne click chemistry approaches are utilized to synthesize sugar‐functionalized all‐cellulose derivatives. All combinations, that is, alkyne‐modified cellulose backbone and azido sugars and vice versa can be applied. Completeness of the conversion of the reactive sites depends on the steric demand of the reactants. The products dissolve in organic media and in water at appropriate degree of substitution.