Click Reactions in Polysaccharide Modification

The idea of modular, simplistic and econonnical synfliesis of structurally and functionally different molecules has also drawn consideration from polysaccharide chemists, and has brought considerable development to fliis field. In addition to click reactions, however they also can quickly synthesize molecules with diverse functional addition. In this section, we have emphasized on some of flie most commonly used click reactions in polysaccharide chennistry, encompassing the well known 

As several novel reactions satisfying the criteria of click chemistry have been exposed in the last decade, we also mention the introduction of these new click reactions to the ground of polysaccharide chemistry, encompassing two metal-free [3 + 2] cycloaddition reactions, and the inverse electron-demand Diels-Alder reaction, In this section we emphasized on the chemistry of the reactions, and try to offer to readers a guide for executing such reactions. Simultaneously, the extremely diverse and controllable structures and functionalities of the click reaction products are established. Various types of chck reactions involved are illustrated in Fig. 4.4. In addition several examples of alkynes and azides generally used to functionalized polysaccharides are mentioned in Table 4.3. 

Reagent structure General reaction condition Polysaccharides 

Propargyl halide Base (NaH, NaOH), 40-50 °C, 72-96 h GeUulose [49-51], chitosan [52], starch, [53] 

Propargyl amine 80 °C, 24 h in DMSO GeUulose (6-tosyl, cellulose) [54] 

---