羟基肉桂醛交叉偶联形成木质素。

Cross-coupling of hydroxycinnamyl aldehydes into lignins.

作者信息

Kim H, Ralph J, Yahiaoui N, Pean M, Boudet A M

机构信息

U.S. Dairy Forage Research Center, USDA-Agricultural Research Service, Madison, Wisconsin 53706, USA.

出版信息

Org Lett. 2000 Jul 27;2(15):2197-200. doi: 10.1021/ol005906o.

DOI:10.1021/ol005906o

PMID:10930242

Abstract

Pathways for hydroxycinnamyl aldehyde incorporation into lignins are revealed by examining transgenic plants deficient in cinnamyl alcohol dehydrogenase, the enzyme that converts hydroxycinnamyl aldehydes to the hydroxycinnamyl alcohol lignin monomers. In such plants the aldehydes incorporate into lignins via radical coupling reactions. As diagnostically revealed by long-range (13)C-(1)H correlative NMR, sinapyl aldehyde (3, 5-dimethoxy-4-hydroxy-cinnamaldehyde) 8-O-4-cross-couples with both guaiacyl (3-methoxy-4-hydroxyphenyl-propanoid) and syringyl (3, 5-dimethoxy-4-hydroxyphenyl-propanoid) units, whereas coniferyl aldehyde cross-couples only with syringyl units.

摘要

通过研究缺乏肉桂醇脱氢酶的转基因植物，揭示了羟基肉桂醛掺入木质素的途径。肉桂醇脱氢酶是一种将羟基肉桂醛转化为羟基肉桂醇木质素单体的酶。在这类植物中，醛类通过自由基偶联反应掺入木质素中。如通过长程(13)C-(1)H相关核磁共振诊断显示，芥子醛(3,5-二甲氧基-4-羟基肉桂醛)与愈创木基(3-甲氧基-4-羟基苯基丙烷)和紫丁香基(3,5-二甲氧基-4-羟基苯基丙烷)单元均发生8-O-4交叉偶联，而松柏醛仅与紫丁香基单元发生交叉偶联。