| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1991: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1990: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
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
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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
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