138663-00-0

Upstream product

• 138571-71-8 3',4',5,7-Tetra-O-methyl-3-O--(+)-catechin 
• 138571-72-9 3-O--3',4',5,7-tetra-O-methyl-(+)-catechin 
• 138571-69-4 3-O-<1-Imidazolyl(thiocarbonyl)>-3',4',5,7-tetra-O-methyl-(+)-catechin 
• 154-23-4 catechin 
• 51079-25-5 (2R,3S)-(+)-catechin 3',4',5,7-tetramethyl ether 
• 154-23-4 catechin hydrate 
• 138571-70-7 3',4',5,7-Tetra-O-methyl-3-O--(+)-catechin 

Downstream Products

• 299412-52-5 (2S)-8-bromo-5,7,3',4'-tetramethoxyflavan 
• 299412-51-4 (2S)-8-[(1R)-1,3-diphenylpropyl]-5,7,3',4'-tetramethoxyflavan 
• 7515-28-8 diphenylmethyl benzoate 
• 1083-30-3 dihydrochalcone 

Relevant academic research and scientific papers

Studies in polyphenol chemistry and bioactivity. 2. Establishment of interflavan linkage regio- and stereochemistry by oxidative degradation of an O-alkylated derivative of procyanidin B2 to (R)-(-)-2,4-diphenylbutyric acid

The assignment of interflavan bond regio- and stereochemistry in oligomeric proanthocyanidins has in the past relied on empirical spectroscopic techniques which are influenced by the conformation of the C rings. Only recently was the 4,8-regiochemistry of procyanidin B2 (3b) firmly established by 2-dimensional NMR methods. We describe herein the proof of 4β-stereochemistry in 3b by oxidative degradation of the derivative 3d bearing differential (O-benzyl and O-methyl) protecting groups in its 'top' and 'bottom' epicatechin moieties, to (R)-(-)-2,4-diphenylbutyric acid. The key elements of the degradative process are (1) removal of the C-3 alcohol functions through a modified Barton deoxygenation employing hypophosphorous acid as the reducing agent; (2) deprotection of the 'top' unit by hydrogenolysis, followed by exhaustive aryl triflate formation with N,N-bis-(trifluoromethanesulfonyl)aniline and DBU in DMF; (3) hydrogenolytic deoxygenation of the 'top' unit over Pearlman's catalyst with concomitant scission of the O-C2 bond; (4) selective oxidation of the 'bottom' unit with NaIO4/RuCl3. The hitherto unreported absolute configuration of (-)-2,4-diphenylbutyric acid was established as R by X-ray crystal structure analysis of the (R)-(+)-α-methylbenzylamine salt. As a corollary, the selectivity of hydrogenolytic and solvolytic reactions of epicatechin-derived tetrasulfonates has been investigated.

On the Radical Deoxygenation of Secondary Alcohols

The derivatives 1c - 1f were prepared from tetramethyl-(+)-catechin (1b).Their radical reduction with tri-n-butyltin hydride or tris(trimethylsilyl)silane in the presence of azobis(isobutyronitrile) as initiator led to (2R)-(-)-3',4',5,7-tetramethoxyflava