Institute of Organic Chemistry and Macromolecular Chemistry, Friedrich Schiller University of Jena, Centre of Excellence for Polysaccharide Research, Humboldtstraße 10, D-07743 Jena, Germany.
Institute of Organic Chemistry and Macromolecular Chemistry, Friedrich Schiller University of Jena, Centre of Excellence for Polysaccharide Research, Humboldtstraße 10, D-07743 Jena, Germany; Laboratory of Fibre and Cellulose Technology, Åbo Akademi University, Porthansgatan 3, FI-20500 Turku, Finland.
Carbohydr Polym. 2015;127:236-45. doi: 10.1016/j.carbpol.2015.03.025. Epub 2015 Mar 20.
The homogeneous tosylation of agarose was studied with respect to the effects of reaction parameters, such as reaction medium, time, and molar ratio, on the reaction course, the degree of substitution (DS) with tosyl/chloro deoxy groups, and the molecular structure. Tosyl agaroses (TOSA) with DS tosyl ≤ 1 .81 could be obtained in completely homogeneous reactions by using N,N-dimethylacetamide (DMA)/LiCl or 1,3-dimethyl-2-imidazolidinone (DMI) as solvents. The products were characterized by FT-IR and NMR spectroscopy and it was demonstrated that two types of substitution pattern can be achieved: (i) non-preferential substitution at position 6 of the 1 → 3-linked β-d-galactose unit (G-6) and position 2 of the 1 → 4-linked 3,6-anyhdro-α-L-galactose unit (LA-2) and (ii) regioselective tosylation at G-6, depending on whether the reaction is performed with or without LiCl. Finally, the nucleophilic displacement reaction of TOSA was studied using azide and ethylenediamine as representative nucleophiles. Novel deoxy-agarose derivatives were obtained that showed an interesting solubility behavior and will be used for creating functional polysaccharide materials.
琼脂糖的均相甲苯化研究了反应参数的影响，如反应介质、时间和摩尔比，对反应过程、取代度（DS）与甲苯/氯脱氧基团和分子结构的影响。使用 N,N-二甲基乙酰胺（DMA）/LiCl 或 1,3-二甲基-2-咪唑烷酮（DMI）作为溶剂，可以在完全均相反应中获得 DS 甲苯≤1.81 的甲苯琼脂糖（TOSA）。通过傅里叶变换红外光谱（FT-IR）和核磁共振光谱（NMR）对产物进行了表征，结果表明可以实现两种取代模式：（i）在 1→3 连接的β-d-半乳糖单元（G-6）的位置 6和 1→4 连接的 3,6-脱水-α-L-半乳糖单元（LA-2）的非优先取代，以及（ii）取决于反应是否进行LiCl，在 G-6 处的区域选择性甲苯化。最后，研究了 TOSA 的亲核取代反应，使用叠氮化物和乙二胺作为代表性亲核试剂。获得了新型的脱氧琼脂糖衍生物，它们表现出有趣的溶解行为，将用于制备功能性多糖材料。
