ASSIGNMENT OF 2D TOCSY SPECTRA OF LIGNINS - THE ROLE OF LIGNIN MODEL COMPOUNDS

The validity of using model compound data to facilitate the interpreta tion of solution-state two-dimensional TOCSY spectra of soluble wood l ignins is demonstrated, The correspondence between model data and lign in correlations was such that it was possible to match the structure a nd stereochemistry of model compounds to structures present in the lig nins by mapping model compound H-1 chemical shift data to the cross pe aks observed in the TOCSY spectra, For systematic comparisons of model data and lignin correlations, an XY scatter plot of model compound si de-chain data was generated and then overlayed on the lignin TOCSY spe ctra, In addition to providing an accurate way of comparing model comp ound data with lignin correlations, this technique permitted the eluci dation of some previously unassigned correlations, In situations where not all possible combinations of model compound side-chain stereochem istry and aromatic ring substitution were available, it was possible t o generate internally consistent side-chain data from substituent effe cts, This allowed the prediction of the mode of attachment of certain inter-unit structures in the lignins.