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Titolo:
LIGNIN-FERULATE CROSS-LINKS IN GRASSES .4. INCORPORATION OF 5-5-COUPLED DEHYDRODIFERULATE INTO SYNTHETIC LIGNIN
Autore:
QUIDEAU S; RALPH J;
Indirizzi:
ARS,US DAIRY FORAGE RES CTR,USDA,1925 LINDEN DR W MADISON WI 53706 ARS,US DAIRY FORAGE RES CTR,USDA MADISON WI 53706 UNIV WISCONSIN,DEPT FORESTRY MADISON WI 53706
Titolo Testata:
Journal of the Chemical Society. Perkin transactions. I
fascicolo: 16, , anno: 1997,
pagine: 2351 - 2358
SICI:
0300-922X(1997):16<2351:LCIG.I>2.0.ZU;2-4
Fonte:
ISI
Lingua:
ENG
Soggetto:
CONIFERYL ALCOHOL; CELL-WALLS; NMR-SPECTROSCOPY; DIFERULIC ACID; COMPONENTS; ESTERS; WHEAT;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
54
Recensione:
Indirizzi per estratti:
Citazione:
S. Quideau e J. Ralph, "LIGNIN-FERULATE CROSS-LINKS IN GRASSES .4. INCORPORATION OF 5-5-COUPLED DEHYDRODIFERULATE INTO SYNTHETIC LIGNIN", Journal of the Chemical Society. Perkin transactions. I, (16), 1997, pp. 2351-2358

Abstract

Ferulates and dehydrodiferulates have a significant role in cross-linking polysaccharides to lignin in grass cell walls. Among the various ferulate dehydrodimers, the 5-5-coupled dehydrodimer ,E)-4,4'-dihydroxy-3,3'-dimethoxy-5,5'-bicinnamate is capable of the most extensive cross-linking into lignin, forming major branch-points, However, current literature fails to recognise the role of radical cross-coupling reactions with lignin monomers/oligomers, Here we demonstrate that a synthetic model for 5-5-coupled dehydrodiferulate polysaccharide esters in grass cell walls biomimetically incorporates into synthetic lignins viaradical coupling mechanisms to produce a range of cross-coupled structures, The incorporation profile is remarkably similar to that for ferulate, Importantly significant coupling at the cinnamoyl 8-position readily occurs, Evidence for the expected incorporation of the 5-5-coupled dehydrodiferulate into the newly discovered dibenzodioxocine structures is readily apparent in HMQC or HSQC spectra. Since some of the structures that dehydrodiferulates are involved in cannot be hydrolytically cleaved, their current 'quantification' is a significant underestimation of the importance of these species. What is clear is that dehydrodiferulates can have a powerful role in effecting lignin-polysaccharlde cross-linking.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/09/20 alle ore 05:36:04