Condensed tannins: direct synthesis, structure, and absolute configuration of four biflavonoids from black wattle bark (‘mimosa’) extract
- 1 January 1978
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Chemical Communications
- No. 16,p. 700-702
- https://doi.org/10.1039/c39780000700
Abstract
Optically pure (+)-2,3-trans-3,4-trans-flavan-3,3′,4,4′,7-pentaol [(+)-mollisacacidin] and (+)-2,3-trans-flavan-3,3′,4′,5,7-pentaol [(+)-catechin] condense rapidly in 0·1 M HCl to give good yields of 4,8-linked diastereoisomeric biflavonoid proanthocyanidins of all-trans and 2,3-trans-3,4-cis-2,3-trans configurations, and also the 4,6-linked all-trans isomer; c.d. comparison thus enables confirmation of the absolute configurations of three known 4,8-linked all-trans biflavonoids from black wattle bark as 2R,3S,4S–2R,3S, and also identification of a fourth as 2R,3S,4R–2R,3S.This publication has 1 reference indexed in Scilit:
- Condensed tannins: determination of the point of linkage in ‘terminal’(+)-catechin units and degradative bromination of 4-flavanylflavan-3,4-diolsJournal of the Chemical Society, Chemical Communications, 1978