Lignin-carbohydrate model compounds. Formation of lignin methyl arabinoside and lignin methyl galactoside benzyl ethers via quinone methide intermediates

摘要

Model compounds for lignin-carbohydrate complex (LCCs) were synthesized from beta-O-4-type quinone methides and methyl glycosides of alpha-L-arabinofuranose and alpha-D-galactopyranose. Both monosaccharides reacted predominantly through primary hydroxy groups with the benzyl position of the dilignol but some secondary C-3 hydroxy groups of galactopyranosides also took part in ether-bond formation. Methyl alpha-L-arabinofuranosides were found to be more reactive than methyl alpha-D-galactopyranosides. LCC model-compound formation via quinone methides gave a mixture of four diastereomers. The diastereomers were isolated using silica gel and HPLC chromatography and all products were characterized by NMR spectroscopy. [References: 20]