Determination of chemical shifts in 6-condensed syringylic lignin model compounds

A small library of 6-substituted syringyl model compounds with aliphatic, carboxylic, phenylic, benzylic alcohols and brominated substituents were prepared. The influence of the substituents on the chemical shifts of the compounds was analyzed. All of model compounds showed a characteristic increase in the C-13 NMR chemical shift of the methoxy group vicinal to the substitution. This C-13 NMR peak and its corresponding correlation peak in HSQC could potentially be used to identify 6-condensation in syringylic lignin samples.

Automated summary

A series of 6-substituted syringyl model compounds with various substituents were prepared and analyzed, showing a characteristic increase in C-13 NMR chemical shift of the methoxy group vicinal to the substitution. This peak could potentially be used to identify 6-condensation in syringylic lignin samples.