Peng J, Lu F, Ralph J
U.S. Dairy Forage Research Center, U.S. Department of Agriculture-Agricultural Research Service, and Department of Forestry, University of Wisconsin-Madison, Madison, Wisconsin 53706.
J Agric Food Chem. 1998 Feb 16;46(2):553-560. doi: 10.1021/jf970802m.
Sixteen lignin dimers were directly isolated by gel permeation and reversed-phase TLC and HPLC from loblolly pine (Pinus taeda L.) sapwood following large-scale application of the new derivatization followed by reductive cleavage (DFRC) procedure. Their structures were elucidated by GC/MS and NMR. These dimers included representatives from all of the common interunit linkages in softwood lignins (beta-1, beta-beta, 5-5, beta-5, and 5-O-4). The DFRC procedure efficiently cleaves beta-aryl ethers, the major structural unit, so beta-ethers were not found among the dimeric products. All but two of the isolated dimers were guaiacyl-guaiacyl (from coniferyl alcohol-derived units in lignin); small amounts of p-hydroxyphenyl/guaiacyl beta-5 and beta-1 dimers were characterized. Several dimers have benzaldehydes as one unit-since aldehydes are not created by the procedure, they are either present in the native lignin or are formed during the minimal preparation of the wood. The dimers isolated and identified here will eventually allow their quantitation to aid in the structural analyses of wide-ranging plant materials.
在大规模应用新的衍生化后还原裂解（DFRC）程序后，通过凝胶渗透、反相薄层色谱和高效液相色谱从火炬松（Pinus taeda L.）边材中直接分离出16种木质素二聚体。通过气相色谱/质谱和核磁共振对它们的结构进行了阐明。这些二聚体包括软木木质素中所有常见单元间连接类型的代表（β-1、β-β、5-5、β-5和5-O-4）。DFRC程序能有效裂解主要结构单元β-芳基醚，因此在二聚体产物中未发现β-醚。除了两种二聚体外，所有分离出的二聚体都是愈创木基-愈创木基型（来自木质素中松柏醇衍生单元）；鉴定出了少量对羟基苯基/愈创木基β-5和β-1二聚体。有几种二聚体以苯甲醛作为其中一个单元——由于该程序不会产生醛，它们要么存在于天然木质素中，要么是在木材的最少预处理过程中形成的。此处分离和鉴定出的二聚体最终将有助于对其进行定量分析，以辅助对多种植物材料进行结构分析。
