Absolute configuration of isosilybin A by X-ray crystallography of the heavy atom analogue 7-(4-Bromobenzoyl)isosilybin A. 2012

Arlene A Sy-Cordero, and Cynthia S Day, and Nicholas H Oberlies
Department of Chemistry and Biochemistry, University of North Carolina at Greensboro , Greensboro, North Carolina 27402, United States.

Isosilybin A (1) is one of the major flavonolignans that constitute silymarin, an extract of the fruits (achenes) of milk thistle (Silybum marianum). The chemistry of the Silybum flavonolignans has been studied for over four decades, and the absolute configuration of 1 has been determined previously by electronic circular dichroism and X-ray crystallography via correlating the relative configuration of the phenylpropanoid moiety to the established absolute configuration of the 3-hydroxyflavanone portion of the molecule. Herein we report the X-ray crystallographic structure of the product of the reaction of 1 with 4-bromobenzoyl chloride, and, thus, the absolute configuration of 1 was established as (2R, 3R, 7″R, 8″R) directly via X-ray crystallography of an analogue that incorporated a heavy atom. The results were consistent with previously reported assignments and verified the absolute configuration of the diastereoisomer of 1, isosilybin B, and the related diastereoisomeric regioisomers, silybin A and silybin B.

UI MeSH Term Description Entries
D008968 Molecular Conformation The characteristic three-dimensional shape of a molecule. Molecular Configuration,3D Molecular Structure,Configuration, Molecular,Molecular Structure, Three Dimensional,Three Dimensional Molecular Structure,3D Molecular Structures,Configurations, Molecular,Conformation, Molecular,Conformations, Molecular,Molecular Configurations,Molecular Conformations,Molecular Structure, 3D,Molecular Structures, 3D,Structure, 3D Molecular,Structures, 3D Molecular
D002942 Circular Dichroism A change from planar to elliptic polarization when an initially plane-polarized light wave traverses an optically active medium. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed) Circular Dichroism, Vibrational,Dichroism, Circular,Vibrational Circular Dichroism
D005638 Fruit The fleshy or dry ripened ovary of a plant, enclosing the seed or seeds. Berries,Legume Pod,Plant Aril,Plant Capsule,Aril, Plant,Arils, Plant,Berry,Capsule, Plant,Capsules, Plant,Fruits,Legume Pods,Plant Arils,Plant Capsules,Pod, Legume,Pods, Legume
D000077385 Silybin The major active component of silymarin flavonoids extracted from seeds of the MILK THISTLE, Silybum marianum; it is used in the treatment of HEPATITIS; LIVER CIRRHOSIS; and CHEMICAL AND DRUG INDUCED LIVER INJURY, and has antineoplastic activity; silybins A and B are diastereomers. 2,3-Dehydrosilybin,Alepa-forte,Ardeyhepan,Cefasilymarin,Durasilymarin,Hepa-Merz Sil,Hepa-loges,HepaBesch,Hepar-Pasc,Heparsyx,Heplant,Lagosa,Legalon Forte,Silibin,Silibinin,Silibinin A,Silibinin B,Silybin A,Silybin B,Silybinin,2,3 Dehydrosilybin,Alepa forte,Hepa Merz Sil,Hepa loges,Hepar Pasc
D012838 Silymarin A mixture of flavonoids extracted from seeds of the MILK THISTLE, Silybum marianum. It consists primarily of silybin and its isomers, silicristin and silidianin. Silymarin displays antioxidant and membrane stabilizing activity. It protects various tissues and organs against chemical injury, and shows potential as an antihepatoxic agent. Carsil,Karsil,Legalon,Silimarin
D013237 Stereoisomerism The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed) Molecular Stereochemistry,Stereoisomers,Stereochemistry, Molecular,Stereoisomer
D015394 Molecular Structure The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds. Structure, Molecular,Molecular Structures,Structures, Molecular
D044947 Flavonolignans Heterodimers of FLAVONOIDS bound to LIGNANS.
D044950 Flavanones A group of FLAVONOIDS characterized with a 4-ketone. 2-Phenyl-Benzopyran-4-Ones,2 Phenyl Benzopyran 4 Ones
D018360 Crystallography, X-Ray The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed) X-Ray Crystallography,Crystallography, X Ray,Crystallography, Xray,X Ray Crystallography,Xray Crystallography,Crystallographies, X Ray,X Ray Crystallographies

Related Publications

Arlene A Sy-Cordero, and Cynthia S Day, and Nicholas H Oberlies
November 1970, Journal of pharmaceutical sciences,
Arlene A Sy-Cordero, and Cynthia S Day, and Nicholas H Oberlies
May 2008, Chirality,
Arlene A Sy-Cordero, and Cynthia S Day, and Nicholas H Oberlies
August 1980, The Journal of antibiotics,
Arlene A Sy-Cordero, and Cynthia S Day, and Nicholas H Oberlies
December 1996, RNA (New York, N.Y.),
Arlene A Sy-Cordero, and Cynthia S Day, and Nicholas H Oberlies
June 1989, The Journal of antibiotics,
Arlene A Sy-Cordero, and Cynthia S Day, and Nicholas H Oberlies
January 1989, Acta biochimica Polonica,
Arlene A Sy-Cordero, and Cynthia S Day, and Nicholas H Oberlies
April 2005, Angewandte Chemie (International ed. in English),
Arlene A Sy-Cordero, and Cynthia S Day, and Nicholas H Oberlies
May 2008, Chirality,
Arlene A Sy-Cordero, and Cynthia S Day, and Nicholas H Oberlies
December 1970, Science (New York, N.Y.),
Copied contents to your clipboard!