104079-74-5Relevant academic research and scientific papers
IODINATION AND DEUTERATION OF CATECHIN DERIVATIVES
Kiehlmann, E.,Lehto, N.,Cherniwchan, D.
, p. 2431 - 2439 (2007/10/02)
The preparation and 1H and 13C nuclear magnetic reonance spectra of ten monoiodocatechin derivatives are described.The iodination of catechin with N-iodosuccinimide (NIS) takes place regiospecifically at C-6 in acetone but preferentially at C-8 in dimethylformamide; both products can be derivatized at oxygen in alkali medium but lose iodine in the presence of acid. 3',4',5,7,-Tetra-O-methylcatechin reacts with NIS regiospecifically at C-8 while catechin pentaacetate resists iodination.The debromination of 6-bromo- and 6,8-dibromocatechin with sodium sulfite in CD3CN/D2O is accompained by H/D-exchange at C-6 and C-8.The synthesis of catechin pentaacetate from partially deuterated catechin and its conversion to terta-O-methylcatechin proceed without H/D-exchange and permit distinction between the H-6 and H-8 chemical shifts.
Synthesis of Condensed Tannins. Part 14. Biflavanoid Profisetinidins as Synthons. The Acid-Induced 'Phlobaphene'Reaction
Young, Desmond A.,Cronje, Annemarie,Botes, Adrienne L.,Ferreira, Daneel,Roux, David G.
, p. 2521 - 2528 (2007/10/02)
Free phenolic - and -2,3-trans-(-)-fisetinidol-(+)-catechin diastereoisomers of both 3,4-trans and 3,4-cis configuration, which serve as synthons for higher oligomers, are available in improved yields from direct condensation, and also via novel 6-iodo-(+)-catechin as an intermediate substrate.Acid-induced transformations of the predominant -all-trans isomer, illustrative of the well-known 'phlobaphene reaction' of condensed tannins, is shown to include ring-isomerization and fission of the inter-flavanoid bond, followed in the latter instance by the alternatives of anthocyanidin formation, positional rearrangement and self-condensation.
