Formation and chemical structures of acid-soluble lignin II: reaction of aromatic nuclei model compounds with xylan in the presence of a counterpart for condensation, and behavior of lignin model compounds with guaiacyl and syringyl nuclei in 72% sulfuric acid
Formation and chemical structures of acid-soluble lignin II: reaction of aromatic nuclei model compounds with xylan in the presence of a counterpart for condensation, and behavior of lignin model compounds with guaiacyl and syringyl nuclei in 72% sulfuric acid
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DOI：
10.1007/s10086-003-0543-9
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发表时间：
2004-01-01
影响因子：
2.9
通讯作者：
Yasuda, S
中科院分区：
文献类型：
--
作者：
Matsushita, Y;Kakehi, A;Yasuda, S
为了阐明酸溶木质素(ASL)中水溶性物质的形成和化学结构，木质素芳香族核模型化合物Creosol(I)和5-甲氧基Creosol(II)与木糖或木聚糖在载脂蛋白的存在下发生缩合反应，反应温度为72%。I的反应主要生成缩合产物。然而，由于甲氧基的空间位阻，II与载脂蛋白的缩合反应受到抑制，并且II在3%SA中回流后与缩合产物一起生成了C-木苷。为了获得在ASL中可溶于CHCl3的物质的信息，用Klason程序处理了含有愈创木基(VIII)和丁香基(X)核的芳基甘油-β-芳基醚的模型化合物。在3%水杨酸中溶解，Vii只产生不溶的聚合产物，而X产生不溶的聚合产物和CHCl3溶解的低分子量产物。这些结果证明了早先的观点，即ASL中的水溶性物质是由丁香基木质素和半纤维素中的单糖单元形成的缩合产物。此外，在ASL中的CHCl3可溶物质似乎是由Klason木质素与紫丁香基核SA处理产生的低分子量降解产物组成。
To elucidate the formation and chemical structures of water-soluble material in acid-soluble lignin (ASL), lignin aromatic nuclei model compounds of creosol (I) and 5-methoxycreosol (II) were reacted with xylose or xylan in the presence of apocynol as a counterpart for condensation in 72% sulfuric acid (SA). The reaction of I gave mainly condensation product. However, the condensation reaction of II with apocynol was suppressed because of steric hindrance from the methoxyl group, and II yielded a C-xyloside after refluxing in 3% SA together with condensation products. To obtain information on CHCl3-soluble material in ASL, model compounds of arylglycerol-beta-aryl ethers with guaiacyl (VIII) and syringyl (X) nuclei were treated by the Klason procedure. VIII gave only insoluble polymerized product, while X gave insoluble polymerized product and CHCl3-soluble low molecular weight products, which were dissolved in 3% SA. These results prove earlier views that water-soluble material in ASL consists of condensation products formed from syringyl lignin and monosaccharide units in hemicellulose. In addition, the CHCl3-soluble material in ASL appears to be composed of low molecular weight degradation products from SA treatment of Klason lignin with the syringyl nucleus.