68415-05-4Relevant articles and documents
Aged red wine pigments as a source of inspiration for organic synthesis - The cases of the color-stable pyranoflavylium and flavylium-(4→8)-flavan chromophores
Chassaing, Stefan,Isorez-Mahler, Géraldine,Kueny-Stotz, Marie,Brouillard, Raymond
, p. 3066 - 3078 (2015/05/04)
Two flavylium-based chromophores peculiar to aged red wine pigments are investigated from a synthetic viewpoint. The condensation between easy-to-prepare 5-hydroxy-4-methylflavylium salts and aldehydes, giving birth to color-stable pyranoflavylium pigments, further proves efficient and wide in scope. A set of some twenty structurally-related flavylium-based pigments has been prepared and structure:color relationships are discussed. Furthermore, the synthesis of the flavylium-(4→8)-flavan chromophore is achieved via a novel three-step sequence. The elaborated sequence starts with an iodine-magnesium exchange from an 8-iodinated flavan, thus generating a magnesiated species that then smoothly reacts with a flavone to furnish an adduct, that finally leads to the expected chromophore via dehydration.
An asymmetric synthesis of (-)-deoxypodophyllotoxin
Bogucki,Charlton
, p. 588 - 593 (2007/10/02)
A Diels-Alder cycloaddition between the fumarate of methyl (S)-mandelate (22) and α-hydroxy-α-aryl-o-quinodimethane 21 produces an endo cycloadduct (23) in 58% yield. The preparation of the precursor to o-quinodimethane 21 and the conversion of cycloadduct 23 to optically pure (-)-deoxypodophyllotoxin (1) is described.