14051-53-7Relevant academic research and scientific papers
An efficient oxyfunctionalisation by dimethyldioxirane of the benzylethereal carbon of flavonoids; a general and useful way to anthocyanidins
Bernini, Roberta,Mincione, Enrico,Sanetti, Anna,Bovicelli, Paolo,Lupattelli, Paolo
, p. 4651 - 4654 (1997)
Compounds with flavonoid structure were selectively oxyfunctionalised at the C-2 carbon atom by DMD. The reaction permitted a new route to flavylium salts.
Photochromic Properties of 2-Hydroxychalcones in Solution and Polymers
Matsushima, Ryoka,Suzuki, Masakazu
, p. 39 - 45 (1992)
A series of substituted 2-hydroxychalcones (HC) were prepared, most of which underwent efficient and clean photochemical conversion into flavylium cations (FV) in acidic solution and polymer film, although strongly dependent on the pH and medium conditions as well as the HC structures. 4'-Methoxy and 4'-dimethylamino derivatives showed relatively high thermal stabilities of the colored mixtures, well-separated absorption bands of the HC and FV forms, almost quantitative conversion from HC to FV in the photostationary-state mixtures, and good photochromic performances in solution and polymer film without suffering from the dissolved oxygen or moisture.A few of them showed relatively high reversibilities in the HC-FV interconversions under special pH and medium conditions.
Hydration of the Flavylium Ion. 3. The Effect of 3-Alkyl Substitution
Devine, David B.,McClelland, Robert A.
, p. 5656 - 5660 (2007/10/02)
An investigation is reported of the transformations undergone by four flavylium salts-two 3-methyl-substituted cations, the 3-methylflavylium ion, and the 4'-methoxy-3-methylflavylium ion-and two cations where an ethylene unit bridges the 3-position and the 2'-position of the phenyl ring, the 5,6-dihydrobenzoxanthylium ion, and the 3-methoxy-5,6-dihydrobenzoxanthylium ion.Three transformations have been identified and studied-a rapid and reversible hydration of the cations to produce a pseudobase, the rapid reversible ring opening of this pseudobase to a (Z)-chalcone, and the slow irreversible cis-trans isomerization of this species to an (E)-chalcone.Rate and equilibrium constants have been obtained for these processes and compared with values previously obtained for 3-H-substituted flavylium ions, the parent flavylium ion itself, and the 4'-methoxyflavylium ion.There is little effect of the alkyl substitution on the pseudobase: (Z)-chalcone equilibration.The ethylene-bridged systems undergo cis-trans isomerization at a similar rate to the 3-H systems, while the 3-methyl systems undergo this reaction about 30 times more slowly.The most significant effect, however, is seen on the flavylium ion hydration equilibrium, the bridged cations being about 2 orders of magnitude more stable than their 3-H-substituted counterparts with these in turn 2 orders of magnitude more stable than the 3-methyl analogues.To explain this, it is proposed that there is a steric interaction involving the 3-hydrogen or 3-methyl substituent and an ortho hydrogen on the nearby phenyl ring, resulting in a twisting of this ring so that it is not coplanar with the benzopyrylium portion of the cation.
