82522-50-7Relevant academic research and scientific papers
Hydration of the Flavylium Ion. 2. The 4'-Hydroxyflavylium Ion
McClelland, Robert A.,McGall, Glenn H.
, p. 3730 - 3736 (1982)
An investigation of the transformations undergone by the 4'-hydroxyflavylium ion in aqueous solution is reported.A rapid initial deprotonation of the hydroxy group occurs, resulting in an anhydro base, the pKa value associated with this ionization being 5.5.A slower transformation follows in which further equilibration occurs with a pseudobase and ring-opened cis-chalcone.The stabilities of the neutral species are very similar, the mixture at equilibrium consisting of 37percent pseudobase, 33percent neutral chalcone, and 30percent anhydro base.This equilibrium is displaced toward flavylium ion in acid solutions (pH 8 direct hydration of the anhydro base occurs.In all solutions with pH >4 a very slow further reaction occurs, resulting in the irreversible formation of trans-2,4'-dihydroxychalcone, the product of thermodynamic control at all pHs.
