105561-65-7Relevant academic research and scientific papers
SYNTHESIS AND CHARACTERIZATION OF PROCYANIDIN DIMERS AS THEIR PERACETATES AND OCTAMETHYL ETHER DIACETATES
Kolodziej, Herbert
, p. 1209 - 1216 (2007/10/02)
Key Word Index - Biomimetic synthesis; procyanidins B1-B8; 3,4-cis-biflavanoid; all--bi--(+)-catechin; 1H NMR parameters. Condensation of (2R,3S,4R or S)-leucocyanidin or the 5,7,3',4'-tetramethyl ether of (2R,3R,4S)-leucocyanidin with flavan-3-ols yielded dimeric flavanoids which were converted to their octamethyl ether diacetates, or the deca-acetates for the 2,3-trans-procyanidin series.Comparison is made of the 1H NMR spectra of the deca-acetate and octamethyl ether diacetate derivatives which lead to useful diagnostic shift parameters characteristic of their structures.Condensation afforded a novel biflavanoid with a 3,4-cis-configuration and a triflavanoid of 'mixed' stereochemistry.
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.
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
HETEROGENEITY OF INTERFLAVANOID BOND LOCATION IN LOBLOLLY PINE BARK PROCYANIDINS
Hemingway, Richard W.,Karchesy, Joseph J.,McGraw, Gerald W.,Wielesek, Richard A.
, p. 275 - 282 (2007/10/02)
Procyanidins B-1 B-3 and B-7 were obtained from Pinus taeda phloem in yields of 0.076, 0.021 and 0.034percent of unextracted dry wt.Procyanidins B-1 and B-7 were produced in relative yields of 2.4:1 by biosynthetically patterned synthesis from catechin and loblolly pine tannins.Partial acid-catalysed thiolytic cleavage of loblolly pine phloem tannins produced (2R,3S,4S)-2,3-cis-3,4-trans-3,3',4',5,7-pentahydroxy-4-phenylthioflavan and both (2R,3R,4R)-2,3-cis-3,4-trans-3,3'4',5,7-pentahydroxy-4-flavan and (2R,3R,4R)-2,3-cis-3,4-trans-3,3',4',5,7-4-flavan in ratios of 3 : 1 demonstrating regio-isomerism of the interflavanoid linkage in the polymeric procyanidins of loblolly pine bark.Key Word Index - Pinus taeda; Pinaceae; loblolly pine; bark; phloem; procyanidins; condensed tannins; interflavanoid linkage; regio-isomerism.
