69912-76-1Relevant academic research and scientific papers
An efficient synthesis of the four mono methylated isomers of (+)-catechin including the major metabolites and of some dimethylated and trimethylated analogues through selective protection of the catechol ring
Cren-Olive, Cecile,Lebrun, Stephane,Rolando, Christian
, p. 821 - 830 (2007/10/03)
The four monomethylated isomers of (+)-catechin in positions 3′, 4′, 5 and 7, two dimethylated derivatives, the 5,7-dimethylcatechin and the 3′, 4′-dimethylcatechin and two trimethylated isomers of (+)-catechin in positions 3′, 5, 7 and 4′, 5, 7 were synthesized by a new method based on successive and selective protections of the various phenol functions present on (+)-catechin. The key step was the selective protection of the catechol ring with dichlorodiphenylmethane and di-tert-butyldichlorosilane.
Oligomeric Flavonoids. Part 16. Novel Prorobinetinidins and the First A-Type Proanthocyanidin with a 5-Deoxy A- and 3,4-cis-C-Ring from the Maiden Investigation of Commercial Wattle Bark Extract
Cronje, Annemarie,Steynberg, Jan P.,Brandt, E. Vincent,Young, Desmond A.,Ferreira, Daneel
, p. 2467 - 2478 (2007/10/02)
Structural examination of the phenolic metabolites of commercially used wattle bark extract reveals the presence of a range of novel flavonoids comprising (-)-epirobinetinidol 1, the first C-methyl proanthocyanidin, (-)-fisetinidol-(4α,8)-6-methyl-(+)-catechin 3, the first prorobinetinidins with 3,4-cis-C-ring configurations 7 and 9, and the unique A-type prorobinetinidin 11 representing the first entry amongst this class of oligoflavonoids exhibiting a 5-deoxy A- and a 3,4-cis-C-ring.They are accompanied by a range of functionalized prorobinetinidin-type tetrahydropyranochromenes 20, 23, 25 and 28 and the trimeric 'isomerization-intermediate' 32, all exhibiting the characteristic structural features that are essential for the use of 'Mimosa' exctract in cold-setting adhesives and leather-tanning applications.In addition, evidence demonstrating that the dynamic A-E conformational equilibrium of flavan-3-ol moieties in condenced tannins may be influenced by external factors is presented.
Selective O-methylation of polyhydroxyflavan-3-ols via benzyl carbonates
Van Dyk, Martha S.,Steynberg, Jan P.,Steynberg, Petrus J.,Ferreira, Daneel
, p. 2643 - 2646 (2007/10/02)
The flavan-3-ols (+)-catechin and (-)-epicatechin were selectively transformed to their 3′,4′-di-O-methyl- and 5,7-di-Omethyl-ethers respectively via benzyl carbonates. Such a regioselectivity is facilitated by marked differences in the pKa values of the
Degradation of (+)-cyanidanol-3 by sodium sulfite in aqueous solution. II. Reactivity of several (+)-cyanidanol-3 derivatives with sodium sulfite
Akimoto,Sugimoto
, p. 3148 - 3154 (2007/10/02)
The reactivity of several (+)-cyanidanol-3 (cianidanol) derivatives with sodium sulfite in aqueous solution was investigated at pH 7.5 and 60°C. 5,7-O-Dimethylcianidanol was degraded by sodium sulfite to yield, a water-soluble degradation product, which w
