Cerium(IV)-mediated oxidation of flavonol with relevance to flavonol 2,4-dioxygenase. Direct evidence for spin delocalization in the flavonoxy radical.
The cerium(IV)-mediated oxidation of 3-hydroxy-4'-methylflavone (1) proceeds by H-atom abstraction forming the flavonoxy radical (7), and the subsequent combination of its resonance forms leads to the 3-hydroxy-4'-methylflavone dehydro dimer (9). The above system serves as direct evidence for the intermediacy of the flavonoxy radical, its spin delocalization, and also indirect evidence for valence tautomerism as a key step on the substrate activation both in the quercetinase and its biomimic model system.
Kaizer
József
J
Department of Organic Chemistry, University of Pannonia, 8201 Veszprém, Hungary.
Ganszky
Ildikó
I
Speier
Gábor
G
Rockenbauer
Antal
A
Korecz
László
L
Giorgi
Michel
M
Réglier
Marius
M
Antonczak
Serge
S
D002563:Cerium / Q000737:chemistry*; D018360:Crystallography, X-Ray; D049308:Dioxygenases / Q000737:chemistry*; D044948:Flavonols / Q000737:chemistry*; D008958:Models, Molecular; D010084:Oxidation-Reduction; D013113:Spin Labels
D044948:Flavonols; D013113:Spin Labels; D002563:Cerium; D049308:Dioxygenases; C121201:flavonol 2,4-dioxygenase