Dimeric beta-ether thioacidolysis products resulting from incomplete ether cleavage

Four beta-ether dimers which result from incomplete beta-ether cleavage of syringyl-guaiacyl lignins following non-optimized thioacidolysis/desulfurization of plant materials were identified. The compounds were; the guaiacyl-guaiacyl dimer 3-(4-hydroxy-3-methoxyphenyl)-2-(2-methoxy-4-propylphenoxy)propan-1-ol, the guaiacyl-syringyl dimer 2-(2,6-dimethoxy-4-propylphenoxy)-3-(4-hydroxy-3-methoxyphenyl)- propan-1-ol, the syringyl-guaiacyl dimer 3-(3,5-dimethoxy-4-hydroxyphenyl)-2-(2-methoxy-4-propylphenoxy)-propan-1-ol, and the syringyl-syringyl dimer 3-(3,5-dimethoxy-4-hydroxyphenyl)-2-(2,6-dimethoxy-4-propylphenoxy)-propan-1-ol. Synthesis of each dimer, by extending dimeric lignin model beta-ether strategies, provided authentication of the structures.