Identification of Side-Chain Structures in a Poplar Lignin Using Three-Dimensional HMQC−HOHAHA NMR Spectroscopy
| Autor: | Gösta Brunow, Michel Bardet, Erja Ämmälahti, Danielle Robert, Ilkka Kilpeläinen |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Softwood
010405 organic chemistry Chemical shift Chemical structure Analytical chemistry Ether 02 engineering and technology General Chemistry Nuclear magnetic resonance spectroscopy 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences chemistry.chemical_compound chemistry Computational chemistry Hardwood Side chain Lignin 0210 nano-technology General Agricultural and Biological Sciences |
| Zdroj: | Journal of Agricultural and Food Chemistry. 46:5113-5117 |
| ISSN: | 1520-5118 0021-8561 |
| DOI: | 10.1021/jf980249o |
| Popis: | The structure of an acetylated 13C-enriched poplar wood lignin preparation was studied using three-dimensional HMQC−HOHAHA NMR spectroscopy. This method takes advantage of the large dispersion of 13C chemical shifts to resolve individual 1H chemical shifts. The whole spin system of a 1H−13C correlation observed in an HMQC spectrum, even for minor components and unknown structural units, can be traced out. It is shown here that both trans- and cis-isomers of 6,7-dihydrodibenzo(e,g)(1,4)-dioxocin, a recently discovered prominent linkage in softwood lignins, occur also in hardwood lignin. Moreover, the poplar lignin preparation contains small amounts of noncyclic α-aryl ether linkages. Signals from a side chain of unknown structure are tentatively assigned to a spiro-cyclohexadienone. Keywords: NMR; 3D HMQC−HOHAHA; lignin |
| Databáze: | OpenAIRE |
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