Department of Chemistry and Biotechnology, Tottori University, Tottori 680-8550, Japan.
Int J Biol Macromol. 2013 Jan;52:72-6. doi: 10.1016/j.ijbiomac.2012.08.012. Epub 2012 Sep 1.
Synthesis of a highly regioselective amphiprotic chitosan derivative was achieved by click chemistry. The Huisgen cycloaddition between 6-azido-6-deoxy-N-pthaloyl-chitosan and methyl propiolate was successfully carried out in the presence of Cu(I) catalyst. After the reaction, both the phthaloyl protecting group and methyl group were completely removed by hydrazine. FT-IR and NMR spectroscopy as well as elemental analysis strongly support the structural uniformity of the desired amphiprotic chitosan derivative, which has both a carboxylic group with a 1,4-triazole linker at the C-6 position and an amino group at the C-2 position per repeating unit. The amphiprotic chitosan derivative was soluble under both acidic and basic aqueous conditions. In contrast, it formed nanoparticle under neutral condition due to the interaction between the positive (-NH(3)(+)) and negative (-COO(-)) ions on the chitosan derivative.
点击化学实现了高度区域选择性两性壳聚糖衍生物的合成。在 Cu(I)催化剂存在下，6-叠氮基-6-脱氧-N-邻苯二甲酰壳聚糖与丙炔酸甲酯之间的 Huisgen 环加成反应顺利进行。反应后，通过肼将邻苯二甲酰保护基和甲基完全去除。傅里叶变换红外光谱、核磁共振波谱和元素分析均强烈支持所需两性壳聚糖衍生物的结构均一性，其每个重复单元在 C-6 位均具有一个带有 1,4-三唑连接基的羧酸基团和一个 C-2 位的氨基。该两性壳聚糖衍生物在酸性和碱性水溶液中均具有良好的溶解性。相比之下，由于壳聚糖衍生物上的正电荷（-NH(3)(+)）和负电荷（-COO(-)）离子之间的相互作用，它在中性条件下形成了纳米颗粒。
