TEMPO-mediated oxidation of (1 → 3)-β-d-glucans
TEMPO-mediated oxidation of (1 → 3)-β-d-glucans
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DOI：
10.1016/j.carbpol.2008.12.040
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发表时间：
2009-06
影响因子：
11.2
通讯作者：
N. Tamura;M. Wada;A. Isogai
中科院分区：
文献类型：
--
作者：
N. Tamura;M. Wada;A. Isogai
将2,2,6,6-四甲基哌啶-1-氧基自由基（TEMPO）介导的氧化应用于不溶于水的（1→3）-β-d-葡聚糖、裸藻淀粉和凝胶多糖，制备水溶性氧化产物。当使用15mmol/g多糖作为主要氧化剂的NaClO添加量与催化量的TEMPO和NaBr在pH 10的水相条件下结合时，在100min内定量获得水溶性TEMPO氧化产物。对TEMPO氧化产物的13C NMR分析表明，裸藻淀粉和凝乳多糖的C6伯羟基通过氧化完全转化为羧酸根。由此，可以获得具有几乎均匀化学结构的新的(1→3)-β-d-聚葡萄糖醛酸钠盐。与凝胶多糖相比，高度结晶的裸藻淀粉将 C6 伯羟基完全氧化为羧酸根需要更长的时间。然而，氧化过程中主链发生明显的解聚，由裸藻淀粉和凝胶多糖制备的水溶性TEMPO氧化产物的聚合度分别仅为68和86。
The 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation was applied to water-insoluble (1→3)-β-d-glucans, paramylon and curdlan, to prepare water-soluble oxidized products. When the addition level of NaClO used as the primary oxidant was 15mmol per gram of the polysaccharide in the combination with catalytic amounts of TEMPO and NaBr under aqueous conditions at pH 10, water-soluble TEMPO-oxidized products were obtained quantitatively within 100min.13C NMR analysis of the TEMPO-oxidized products revealed that the C6 primary hydroxyl groups of both paramylon and curdlan were completely converted to carboxylate groups by the oxidation. Thus, new (1→3)-β-d-polyglucuronic acid sodium salts having almost homogeneous chemical structures can be obtained. The highly crystalline paramylon took longer time for the complete oxidation of the C6 primary hydroxyls to carboxylate groups than curdlan. However, remarkable depolymerization occurs on main chains during the oxidation, and the degrees of polymerization of the water-soluble TEMPO-oxidized products prepared from paramylon and curdlan were only 68 and 86, respectively.