NMR Assignment for Diaryl Ether Structures (4–O–5 Structures) in Pine Wood Lignin

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• 作者：Yanding Li ; Takuya Akiyama ; Tomoya Yokoyama ; Yuji Matsumoto
• 刊名：Biomacromolecules
• 出版年：2016
• 出版时间：June 13, 2016
• 年：2016
• 卷：17
• 期：6
• 页码：1921-1929
• 全文大小：494K
• 年卷期：0
• ISSN：1526-4602

文摘

A 4–O–5-tetramer lignin model compound carrying β–O–4 linkages on each of the side-chain moieties was synthesized, as well as 4–O–5-coupled dehydrodiconiferyl alcohol. By comparison with their NMR data, two cross-signals in the HSQC spectrum of pine milled wood lignin recorded in DMSO-d₆ were assigned to H2/C2 and H6/C6 correlations on the aromatic rings of 4–O–5-linked units. Although the H2/C2 correlation peak appeared in the same region as syringyl units, nitrobenzene oxidation of the pine lignin did not yield any syringyl-type product, but did release a 4–O–5-type product.