22425-60-1Relevant academic research and scientific papers
Oligomeric flavanoids, part 29: Structure and synthesis of novel ether- linked [4-O-4] bis-teracacinidins
Coetzee, Johan,Malan, Elfranco,Ferreira, Daneel
, p. 9153 - 9160 (2007/10/03)
The rare series of proteracacinidin-type oligoflavanoids is extended by identification of two novel [4-O-4] ether-linked analogues 7 and 10 from the heartwood of Acacia galpinii. Their structures and absolute configuration were established via spectroscopic methods and by stereoselective synthesis from the appropriate leucoteracacinidin flavan-3,4-diol precursors.
Synthesis of Condensed Tannins. Part 1. Stereoselective and Stereospecific Syntheses of Optically Pure 4-Arylflavan-3-ols, and Assessment of their Absolute Stereochemistry at C-4 by means of Circular Dichroism
Botha, Jacobus J.,Young, Desmond A.,Ferreira, Daneel,Roux, David G.
, p. 1213 - 1219 (2007/10/02)
Stereoselective and also stereospecific condensation at C-4 of flavan-3,4-diols of known absolute configuration with phloroglucinol and resorcinol in acid medium proceeds at ambient temperatures with partial retention of configuration for 2,3-trans-isomers and with inversion for 2,3-cis-analogues.Circular dichroism spectra of the resultant 4-arylflavan-3-ols all exhibit multiple Cotton effects.The sign of high intensity Cotton effects to low wavelength, contributed by aryl chromophores at C-4, may almost invariably be correlated with the absolute configuration at this chiral centre of 2,3-trans-3,4-trans, 2,3-trans-3,4-cis, and 2,3-cis-3,4-trans-isomers.
