81410-22-2Relevant 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 12. Direct Access to - and -all-2,3-cis-Procyanidin Derivatives from (-)-Epicatechin: Assessment of Bonding Positions in Oligomeric Analogues from Crataegus oxyacantha L.
Kolodziej, Herbert,Ferreira, Daneel,Roux, David G.
, p. 343 - 350 (2007/10/02)
Synthesis of methyl ester acetates of - and -all-2,3-cis-procyanidin biflavanoids is effected by oxidative functionalization of (-)-epicatechin tetramethyl ester with lead tetra-acetate, and condensation of the resultant 2,3-cis-flavan-3,4-diol
Tannins and Related Compounds. Part 13. Isolation and Structures of Trimeric, Tetrameric, and Pentameric Proanthicyanidins from Cinnamon
Nonaka, Gen-ichiro,Morimoto, Satoshi,Nishioka, Itsuo
, p. 2139 - 2145 (2007/10/02)
A proanthocyanidin trimer, two tetramers, and a pentamer have been isolated in their free phenolic forms from cinnamon, the bark of Cinnamomum zeylanicum (Lauraceae).Partial acid-catalysed degradation of these tannins with phenylmethanethiol, in conjunction with 1H- and 13C-n.m.r. analysis, has unequivocally established their structures as epicatechin-(4β->8, 2β->7)epicatechin-(4α->8)-epicatechin (5); epicatechin-(4β->8)epicatechin-(4β->8, 2β->7)-epicatechin-(4α->8)-epicatechin (6); epicatechin-(4β->6)-epicatechin-(4β->8, 2β->7)-epicatechin-(4α->8)-epicatechin (7); and epicatechin-(4β->8)-epicatechin-(4β->8)epicatechin-(4β->8, 2β->7)-epicatechin-(4α->8)-epicatechin (8).
Electrophilic Aromatic Substitution of Catechins: Bromination and Benzylation
McGraw, Gerald W.,Hemingway, Richard W.
, p. 973 - 978 (2007/10/02)
Relative yields of C-6, C-8, and C-6 and C-8 substituted catechins obtained from the reaction of (+)-catechin or 3',4',5,7-tetra-O-methyl-(+)-catechin with pyridinium hydrobromide-perbromide, bromine, p-hydroxybenzyl alcohol, or o-hydroxybenzyl alcohol sh
