118964-23-1Relevant academic research and scientific papers
STRUCTURE AND SYNTHESIS OF PHLOBATANNINS RELATED TO (-)-FISETINIDOL-(-)-EPICATECHIN PROFISETINIDINS
Steynberg, Jan P.,Burger, Johann F. W.,Cronje, Annemarie,Bonnet, Susan L.,Malan, Johannes, C. S.,et al.
, p. 2979 - 2989 (2007/10/02)
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
Steynberg, Jan P.,Burger, Johann F. W.,Young, Desmond A.,Brandt, Edward, V.,Steenkamp, Jacobus A.,Ferreira, Daneel
, p. 3331 - 3338 (2007/10/02)
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
