An artificial lignin polymer containing only the β-O-4 substructure was synthesized. The procedure consists of two key steps: 1) polycondensation of a brominated monomer by aromatic Williamson reaction; and 2) subsequent reduction of the carbonyl polymer. 13C-NMR and HMQC spectra of the polymer were consistent with β-O-4 substructures in milled wood lignin isolated from Japanese fir wood. The weight average degree of polymerization (DPw) ranged from 19.5 to 30.6, which is comparable to enzymatically synthesized artificial lignin from p-hydroxycinnamyl alcohols (dehydrogenation polymer, DHP) and some isolated lignins. Using this new lignin model polymer, it will now be possible to reinvestigate the properties and reactivity of the main lignin structure in terms of its polymeric character.
合成了一种仅含有β-O-4亚结构的人工
木质素聚合物。该过程包括两个关键步骤:1) 通过芳香威廉姆森反应对
溴化单体进行聚缩合;2) 随后对羰基聚合物进行还原。聚合物的13C-NMR和HMQC谱与从日本冷杉木材中分离出的木材
木质素中的β-O-4亚结构一致。聚合物的重量平均聚合度(DPw)范围为19.5至30.6,与从对羟基
肉桂醇酶合成的人工
木质素(脱氢聚合物,
DHP)和一些分离的
木质素相当。利用这种新的
木质素模型聚合物,现在将有可能重新研究主要
木质素结构在其聚合物特性方面的性质和反应性。