104079-73-4

Upstream product

• 186581-53-3 diazomethane 
• 108-24-7 acetic anhydride 
• 130932-27-3 (2R,3R,8R,9S,10S)-2,8-Bis-(3,4-dihydroxy-phenyl)-10-(2,4-dihydroxy-phenyl)-3,4,9,10-tetrahydro-2H,8H-pyrano[2,3-f]chromene-3,5,9-triol 
• 119065-89-3 (-)-fisetidinol-(4β,8)-(+)-catechin-O-methyl ether 
• 119002-92-5 8,9-trans-9,10-trans-tetrahydropyrano<2,3-h>chromene 
• 119067-92-4 8,9-cis-9,10-trans-tetrahydro-2H,8H-pyrano<2,3-h>chromane 
• 118964-34-4 (-)-Fisetinidol-(4α,8)-(+)-catechin 4-O(E)-methyl ether 
• 119002-92-5 (2R,3S,8R,9S,10S)-10-(2,4-Dihydroxy-phenyl)-8-(3,4-dihydroxy-phenyl)-2-(3-hydroxy-4-methoxy-phenyl)-3,4,9,10-tetrahydro-2H,8H-pyrano[2,3-f]chromene-3,5,9-triol 
• 57526-59-7 (2R,3S,4S)-2,3-trans-3,4-trans-3,3',4',7-tetrahydroxy-4-<(2R,3S)-2,3-trans-3,3',4',5,7-pentahydroxyflavan-8-yl>flavan 

Relevant academic research and scientific papers

STRUCTURE AND SYNTHESIS OF PHLOBATANNINS RELATED TO (-)-FISETINIDOL-(-)-EPICATECHIN PROFISETINIDINS

Several members of the class of natural 'phlobaphene' condensed tannins, representing the products of C-ring isomerization of (-)-fisetinidol-(4α,8)-(-)-epicatechin profisetinidins have been characterized.These comprise four functionalized tetrahydropyranochromenes, two -analogues and four -regioisomers.A novel protocol of effecting differentiation between the regio-isomers based on homonuclear NOE difference spectroscopy (1H NMR) is proposed.The structures of some of the natural products were confirmed by synthesis via base-catalysed rearrangement of their presumed precursors.Under these mild alkaline conditions, the biflavanoids are susceptible to epimerization at C-2 (F-ring) hence leading to conversion of a (-)-epicatechin to a (-)-catechin DEF moiety.The natural occurence of pyran rearranged analogues related to both these units presumably reflects similar mechanisms for the in vivo and in vitro processes.

OLIGOMERIC FLAVANOIDS. PART 4. BASE-CATALYSED CONVERSIONS OF (-)-FISETINIDOL-(+)-CATECHIN PROFISETINIDINS WITH 2,3-TRANS-3,4-CIS-FLAVAN-3-OL CONSTITUENT UNITS

Additional novel members of the class of natural 'phlobaphene' condensed tannins, representing the products of c-ring isomerization of 2,3-trans-3,4-cis-(-)-fisetinidol units present in (4β,6)- and (4β,8)-biflavanoid profisetinidins have been characterize

OLIGOMERIC FLAVANOIDS. PART 3. STRUCTURE AND SYNTHESIS OF PHLOBATANNINS RELATED TO (-)-FISETINIDOL-(4α,6)- AND (4α,8)-(+)-CATECHIN PROFISETINIDINS

Several members of the novel class of natural 'phlobaphene' condensed tannins, representing the products of c-ring isomerization of 2,3-trans-3,4-trans-(-)-fisetinidol units present in (4,6)- and (4,8)-biflavanoid profisetinidins, have been charcterized b

Synthesis of Condensed Tannins. Part 14. Biflavanoid Profisetinidins as Synthons. The Acid-Induced 'Phlobaphene'Reaction

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.