灰毡毛忍冬皂苷乙的化学结构和波谱特征

灰毡毛忍冬皂苷乙{Macranthoidin B,3-O-β-D-吡喃葡萄糖(1→4)-β-D-吡喃葡萄糖(1→3)-α-L-吡喃鼠李糖(1→2)-α-L-吡喃阿拉伯糖基-28-O-β-D-吡喃葡萄糖(1→6)-β-D-吡喃葡萄糖基-常春藤皂苷}进行了1H和13C NMR检测,纠正了文献结构式错误,补充和纠正了文献1HNMR数据,明确区分该化合物19个羟基的归属,通过DEPT、1 H-1H COSY、HSQC、HMBC等1D、2D NMR技术,对该化合物所有的1H和13C NMR信号进行了全归属和详细解析.

Homogeneous Acetylation of Cellulose at Relatively High Concentrations in an Ionic Liquid

At relatively high cellulose mass concentrations(8%,10%,and 12%),homogeneous acetylation of cellulose was carried out in an ionic liquid,1-allyl-3-methylimidazolium chloride(AmimCl).Without using any catalyst,cellulose acetates(CAs)with the degree of substitution(DS)in a range from 0.4 to 3.0 were synthesized in one-step.The effects of reaction time,temperature and molar ratio of acetic anhydride/anhydroglucose unit(AGU) in cellulose on DS value of CAs were investigated.The synthesized CAs were characterized by means of FT-IR, NMR,and solubility,mechanical and thermal tests.After the acetylation,the used ionic liquid AmimCl was easily recycled and reused.This study shows the potential of the homogeneous acetylation of cellulose at relatively high concentrations in ionic liquids in future industrial applications.