Molecular design and utilization of hybid-functional cellulose derivatives

纤维素分子的结构特征是在重复的无水葡萄糖单元中有三个羟基。考虑到这些羟基的反应性，使我们有可能设计在单分子中具有多种功能的高级纤维素衍生物。我们计划制备一种在6-0位带有长链烷基的杂化功能纤维素衍生物，以期改善其溶解性和热学性质，并在2-0位和3-0位具有特殊功能。研究结果如下：1)以商品苯甲酸甲酯或对羟基二苯甲酮为原料，通过关键中间体4-羟基三苯醇，合成了具有不同烷基链长的4-烷氧基三甲基氯化物，它们与纤维素酶的6-0位发生区域选择性反应。3)对制备纤维素的开环聚合单体的合成方法进行了改进，给出了制备纤维素的开环聚合单体的合成方法，反应步骤少，总收率高。从合成的角度来看，单体的3-O-AllyI基团比苄基更有用。4)所有可能的7种区域选择性甲基化纤维素都是由开环聚合产物合成的。因此，该方法可用于制备区域选择性取代的长链纤维素衍生物，可转化为具有磁性或电导性的杂化功能纤维素衍生物。

The structural feature of cellulose molecule is to have three hydroxyl groupsin the repeating anhydro glucose unit. Considering the reactivity of these hydroxyl groups enable us to open interesting possibilities to design advanced cellulose derivatives with multiple functions in the single molecule.We planned to preare a hybrid-functional cellulose derivatives with long chain alkyl group at 6-0-position expecting the improved solubility and thermal property, and special functions at 2- and 3-0-positions. The results are as follows:1) Nobel etherification reagents,4-alkyloxytrityl chlorides with different alkyl chain lengths which regioselectively reacts with 6-0-psition of cellulsoe, were synthesized from commercial methyl benzoate or p-hydroxybenzophenone via a key intermediate, 4-hydroxytrityl alcohol.2) The novel reagents were found to react regioselectively with 6-O-position of methyl a-D-glucose orcellulose. The obtained, cellulose derivatives showed improved solubility and melted with liquid crystalline property.3) The synthetic method of ring-opening polymerization monomer for preparing cellulose was improved to give.Higher overall yields with fewer reaction steps. 3-O-AllyI group of the monomer was indicated to be more useful than benzyl group from the synthetic point of view.4) All possible 7 regioselectively-methylated celluloses were prepared from the ring-opening polymerization products. Thus, the method can be applied for the preparation of regioselectivly-substituted cellulose derivatives with long chain, which may be converted hybrid-functional cellulose derivatives with magnetism or electro-conductivity.