65085-09-8Relevant articles and documents
Oligomeric flavanoids. Part 27. Interflavanyl bond formation in procyanidins under neutral conditions
Steynberg, Petrus J.,Nel, Reinier J.J.,Van Rensburg, Hendrik,Bezuidenhoudt, Barend C.B.,Ferreira, Daneel
, p. 8153 - 8158 (2007/10/03)
Dimethyl(methylthio)sulfonium tetrafluoroborate (DMTSF) and silver tetrafluoroborate (AgBF4) activate the C4-S bond in the 4-thioethers of flavan-3-ols toward carbon nucleophiles to permit formation of the interflavanyl bond in procyanidins under neutral conditions.
Synthesis of Condensed Tannins. Part 13. The First 2,3-trans-3,4-cis-Procyanidins: Sequence of Units in a 'Trimer' of Mixed Stereochemistry
Delcour, Jan A.,Serneels, Edward J.,Ferreira, Daneel,Roux, David G.
, p. 669 - 676 (2007/10/02)
The condensation of (+)-leucocyanidin with (-)-epicatechin initiates a succession of substitutions leading mainly to the introduction of -2,3-trans-3,4-procyanidin units, but also to the incorporation of 'terminal' moieties which possess the hitherto unique 3,4-cis-procyanidin configuration.The bonding patterns in the products, and also the sequence of units in one of the 'trimers' of mixed stereochemistry, are resolved by (1)H n.m.r. spectroscopy through selective use of solvents at elevated temperatures.