732298-08-7Relevant articles and documents
Asymmetric total synthesis of talienbisflavan A
Huang, Deng-Ming,Li, Hui-Jing,Wang, Jun-Hu,Wu, Yan-Chao
, p. 585 - 592 (2018/02/07)
The first asymmetric total syntheses of talienbisflavan A and bis-8,8′-epicatechinylmethane as well as a facile synthesis of bis-8,8′-catechinylmethane has been accomplished from readily available starting materials by using a newly developed direct regio
Total synthesis of 14C-labeled procyanidin B2
Viton, Florian,Landreau, Cyrille,Rustidge, David,Little, Gill,Robert, Fabien,Williamson, Gary,Barron, Denis
, p. 371 - 374 (2011/05/05)
During the last decades, many in vitro and in vivo studies have shown the beneficial effects on health of procyanidins. However, their absorption and metabolism is still not fully understood and some aspects are still controversial. In order to have a clearer picture of the metabolism of procyanidins, the use of labelled compounds is essential. In this context, the enantioselective synthesis of 14C-radiolabelled procyanidin B2 was developed in our laboratories. It was achieved in fourteen 'hot' steps, involving as key steps the Sharpless dihydroxylation of an elaborated alkene, a stereoselective intramolecular cyclization to benzylated (+)-catechin and the condensation of two (-)-epicatechin units. 11 mCi of protected procyanidin B2 were obtained from 524 mCi of potassium [14C]cyanide. Copyright
PREPARATION OF (+)-CATECHIN, (-)-EPICATECHIN, (-)-CATECHIN, (+)-EPICATECHIN, AND THEIR 5,7,3',4'-TETRA-O-BENZYL ANALOGUES
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Page/Page column 13; 28-29, (2010/11/25)
Processes for preparing racemic mixtures of 5,7,3',4'-tetra-O-benzyl-(±)-catechin and (±)-epicatechin involves (i) condensing 2-hydroxy-4,6-bis(benzyloxy)-acetophenone and 3,4-bis(benzyloxy)benzaldehyde, cyclizing the resulting compound, oxidizing the resulting compound; (ii) dihydroxylating (E)-3-(3',4'-bis(benzyloxy)phenyl)prop-2-ene-1 -ol and reducing the 1 ,2-diol; or (iii) coupling 3,5-bis(benzyloxy)phenol with (£)-3,5-bis(benzyloxy)-2-(3',4'-bis(benzyloxy)phenyl)allyl)phenol and cyclizing the resulting chalcone. A process for preparing the benzylated epimers of catechin and epicatechin involves seven steps. 3,4-Bis(benzyloxy)benzaldehyde is coupled with 2-hydroxy-4,6-benzyloxy-acetophenone to form a chalcone. The chalcone is selectively reduced to an alkene. The phenolic group of the alkene is protected. The protected alkene is asymetrically dihydroxylated. The resulting compound is deprotected, cyclized, and finally hydrolyzed. Epimers resulting from these processes are chemically resolved or separated by chiral high pressure liquid chromatography. Also disclosed is a method for preparing enantiomerically pure 5,7,3',4'-tetra-O-benzyl-(+)-catechin from a racemic mixture using dibenzoyl-L-tartaric acid monomethyl ester. Further, disclosed is an improved process for preparing dibenzoyl-L-tartaric acid monomethyl ester.