Defined Chitosan-based networks by C-6-Azide–alkyne “click” reaction

Synthesis and photochromic response of a new precisely functionalized chitosan with “clicked” spiropyran

“…2). Moreover the 1 H and 13 C NMR spectra were in accordance to the already reported ones (Zampano et al, 2010). The degree of substitution with -N 3 groups per pyranose ring (DS-N 3 ) was 0.28, as estimated by elemental analysis.…”

“…The chitosan modification to N 3 -functionalyzed-N-phthaloylchitosan was carried out in two reaction steps, as reported by Zampano et al (2010). Briefly, in the first reaction step chitosan (5.0 g, 31 mmol of monomer) was reacted with phthalic anhydride (11.5 g, 78 mmol) in DMF (100 mL) at 130 • C under nitrogen atmosphere for 6 h. The mixture was then precipitated in icewater, collected by filtration, washed by Soxhlet extraction with ethanol for 8 h and dried under vacuum for 24 h. Elemental analysis: found C55.87, H4.52, N3.75.…”

“…The Cu(I) catalyzed azide-alkyne [3 + 2] dipolar cycloaddition (Finn, Kolb, Fokin, & Sharpless, 2008) (click reaction) has recently become one of the most popular "click" reactions in macromolecular chemistry being extremely regio-selective and occurring under mild conditions (Binder & Sachsenhofer, 2007;Liebert, Hänsch, & Heinze, 2006). To this regard, the high versatility of 6-azido-6-deoxy, N-phthaloyl derivative of chitosan (PH-N 3 ) as reagent in the "click" reaction with mono-or dialkyne has been recently demonstrated by our group (Zampano, Bertoldo, & Ciardelli, 2010).…”

Polysaccharides: The “Click” Chemistry Impact

“…In 2010, three research groups published their work on the development of new gels from three different polysaccharides (cellulose, chitosan and guar gum) and a spacer molecule to cross-link these polysaccharides. Zampano and co-workers [35] used an aliphatic or an aromatic chain bearing two alkyne functions to cross-link the 6-deoxy-6-azido chitosan ( Figure 13). The azido-functionalized products reacted efficiently in Cu(I)-catalyzed "click" cycloaddition at room temperature with a model reagent phenylacetylene, the di-alkynes 1,7-octadiyne and 1,4-diethynylbenzene used for cross-linking.…”

Synthesis of amphiphilic aminated inulin via ‘click chemistry’ and evaluation for its antibacterial activity

“…12 It has been widely employed to build up polymers with complex architectures. [13][14][15] The team of Saimoto prepared new chitosan derivatives containing triazolyl moieties at the C6 position of glucosamine units by coupling between azide and propargyl groups of chitosan via a 1,3-dipolar cycloaddition. 16,17 The modification of carbohydrate polymers by 'click chemistry' will help to overcome their disadvantages, such as low selectivity, complicated reaction conditions, various side reactions, and low yields, and remarkably improve their substitution efficiency.…”