cis–trans Isomerization of silybins A and B

Methods were developed and optimized for the preparation of the 2,3-cis- and the 10,11-cis-isomers of silybin by the Lewis acid catalyzed (BF(3)∙OEt(2)) isomerization of silybins A (1a) and B (1b) (trans-isomers). The absolute configuration of all optically pure compounds was determined by using NMR...

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Detalles Bibliográficos
Autores principales: Novotná, Michaela, Gažák, Radek, Biedermann, David, Di Meo, Florent, Marhol, Petr, Kuzma, Marek, Bednárová, Lucie, Fuksová, Kateřina, Trouillas, Patrick, Křen, Vladimír
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Beilstein-Institut 2014
Materias:
Full Research Paper
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4077359/
https://www.ncbi.nlm.nih.gov/pubmed/24991256
http://dx.doi.org/10.3762/bjoc.10.105
Descripción
Sumario:Methods were developed and optimized for the preparation of the 2,3-cis- and the 10,11-cis-isomers of silybin by the Lewis acid catalyzed (BF(3)∙OEt(2)) isomerization of silybins A (1a) and B (1b) (trans-isomers). The absolute configuration of all optically pure compounds was determined by using NMR and comparing their electronic circular dichroism data with model compounds of known absolute configurations. Mechanisms for cis–trans-isomerization of silybin are proposed and supported by quantum mechanical calculations.

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