Effect of Hydrophobic Resion of Hemicelluloses on Dehydrogenative Polymerization of Monolignols

脱氢聚合物(DHP)作为木质素的模型，用于研究天然木质素的化学结构和合成。然而，由Froudenberg开发的Zulaufverpharen和Zutroverfahren等不同方法制备的DHPS的某些化学和物理性质与天然木质素有所不同。尤其是芥子醇脱氢聚合的反应产物不同于针叶醇-DHP在活体树上的反应产物。在植物细胞壁中，木质素通过木质化过程沉积在多糖的基质中。为了证明半纤维素对脱氢聚合的影响，用Zulaufverfahren方法对芥子醇在果胶存在下用辣根过氧化物酶/H202进行脱氢反应。主要反应产物为丁香甘油-辛烷醇醚、d、L-西林格树脂酚和一个未知化合物，乙酰化后用薄层色谱分离，并用核磁共振和MS SPEC…进行了分析。更多的对比度。结果该未知化合物鉴定为1，5-di(3，5-dimethoxy-4-hydroxyphenyl)-1-hydroxy-2-hydroxymethyl-1-pentene(b-r类型)。这种亚结构可能存在于天然木质素中，并通过扩展的苯二亚胺中间体进行离子反应而产生。考察了反应介质对芥子醇脱氢聚合的影响。采用Zulaufverfahren法在不同pH值和不同极性条件下，用FeCl3和过氧化物酶/H202对芥子醇进行脱氢反应。结果表明，当芥子醇用FeCl3脱氢时，b-0-4型二聚体的比例随着二氧六环含量和酸度的增加而增加。这一现象可以解释为芥子醇的甲氧基在低极性和低pH溶液中的E效应被抑制。而过氧化物酶/H_(202)芥子醇则以丁香醇为主。因此，可以认为这两种反应机制是不同的，可能是自由基载体作为中介通过木质化作用氧化植物细胞壁中的木质素。较少

Dehydrogenation polymer (DHP) is using as a model of lignins to research the chemical structure and the blosyntheses of native lignins. However, some chemical and physical properties of DHPs, which are prepared by any methods, Zulaufverpharen and Zutropverfahren deveroped by Froudenberg differs from the native lignin. Especially, the reaction products of the dehydrogenative polymerization of sinapyl alcohol differs from the reaction in the living tree compared with the coniferyl alcohol-DHP. In a plant cell wall, lignin was deposited in the matrix of polysaccharides through the lignification process. To demonstrate the effect of hemicelluloses on dehydrogenative polymerization, sinapyl alcohol was dehydrogenated with horseradish peroxidase/H202 in the presence of pectin by Zulaufverfahren method. Main reaction products, which were syringylglycerol-bsinapyl alcohol ether, d, l-siringaresinol and an unknown compound, were isolated by PTLC after acetylation and analyzed by NMR and MS spec … More trometry. As a result, the unknown compound identified 1, 5-di(3, 5-dimethoxy-4-hydroxyphenyl)-1-hydroxy-2-hydroxymethyl-1-pentene(b-r type). This substructure would be present in native lignin, and generated by ionic reaction through ihe extended quinonemethide-intermediate. Effect of reaction media on dehydrogenation polymerization of sinapyl alcohol were examined. Sinapyl alcohol was dehydrogenated with FeCl3 and peroxidase / H202 under various pH and polarity by Zulaufverfahren method. From these results, when sinapyl alcohol was dehydrogenated with FeCl3, the ratio of b-0-4 type dimeric compound was increased with increasing of dioxane content and acidity. This phenomenon could be explained that the E-effect of methoxyl group of sinapyl alcohol was suppressent in low polar and low pH solbents. However, with peroxidase/H202 sinapyl alcohol gave syringaresinol mainly. Hence, it could be considered that there was difference between the two reaction mechanisms, and it might be suggested that the radical carrier as a mediater oxidated lignols in the plant cell wall through the lignification. Less