Eco-friendly and efficient modification of native hemicelluloses via click reactions

This paper reports the functionalization of heterogeneous hemicelluloses from Tacuara cane using the "click reaction". The synthesis was designed as a two-step strategy. The first step was the introduction of azido groups onto the backbone of hemicellulose by etherification of the natural polymer with 1-azido-2,3-epoxypropane to obtain HC-N-3. In the second step, different terminal alkynes functionalized with aliphatic and aromatic groups were grafted onto HC-N-3 by copper-catalyzed azide-alkyne cycloaddition (CuAAC). Hemicellulose-based products were obtained in high yields and further characterized using spectroscopic (NMR-H-1 and ATR-FTIR), thermal (TGA) and chromatographic techniques (HPAEC) evidencing that click chemistry is an attractive modification strategy to graft hemicellulose with different molecules through a triazole ring. This methodology was designed as a possible approach to valorise native hemicelluloses and to facilitate their use as a potential platform to support different reagents or biomolecules.