2-DIMENSIONAL H-1-H-1 CHEMICAL-SHIFT CORRELATION AND J-RESOLVED NMR-STUDIES ON ISOLATED AND SYNTHETIC LIGNINS

1H-1H COSY and J-resolved 2D NMR spectra of acetylated samples of milled wood lignin (MWL), suspension culture (SC) lignin (isolated from the extra-cellular fluid of cell cultures) and the dehydrogenation polymer of coniferyl alcohol (DHP) were recorded. The 1H-1H COSY experiments showed crosspeaks consistent with known structural units in these lignins. In addition, the presence of arylglycerol and 3-arylpropanol structures was confirmed. The COSYexperiments also showed that α—O—4 aryl ether and β—C—1 linkages in these lignins each accounted for no more than about 2% of the phenylpropane units. The 2D 7-resolved experiment was useful in the case of the DHP and SC lignins; allowing separation of the overlapping multiplets from Hβ in the coniferyl alcohol endgroups and Ha in the β—O—4 aryl ether structures. © 1990, Walter de Gruyter. All rights reserved.