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Proanthocyanidins acid-catalysed cleavage

Fig. 9B.3 Acid-catalysed cleavage of proanthocyanidin interflavanic linkages and subsequent reactions, namely oxidation to anthocyanidin and nucleophilic (Nu) addition... Fig. 9B.3 Acid-catalysed cleavage of proanthocyanidin interflavanic linkages and subsequent reactions, namely oxidation to anthocyanidin and nucleophilic (Nu) addition...
As stated above, flavonoids react as nucleophiles through their C8 and C6 positions. Acid-catalysed cleavage of the interflavanic linkages of proanthocyanidins (cf. Eig. 9B.3) also takes place spontaneously in wine, yielding an intermediate electrophile. A third group of reactions involves the o-diphenolic B-ring which can be oxidized to electrophilic quinones. Several mechanisms arise from these reactivities. [Pg.478]

B.3.3.1 Reactions Based on Acid-Catalysed Cleavage of Proanthocyanidins... [Pg.479]

The reaction starts with acid catalysed cleavage of a proanthocyanidin interfla-vanic linkage (Figs. 9B.3 and 9B.5(1)). The intermediate carbocation thus generated then undergoes nucleophilic addition. When the nucleophile is another flavanol (Fig. 9B.5(2a)), the product is a new proanthocyanidin molecule. As a result of this... [Pg.479]

See other pages where Proanthocyanidins acid-catalysed cleavage is mentioned: [Pg.566]    [Pg.566]    [Pg.471]    [Pg.472]    [Pg.477]    [Pg.486]    [Pg.566]    [Pg.359]   
See also in sourсe #XX -- [ Pg.479 , Pg.481 ]



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Acidic cleavage

Cleavage acids

Proanthocyanidin

Proanthocyanidins

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