- A short synthesis of rhaponticin and its 3''-fluoroanalog via a wittig/heck-mizoroki route
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Rhaponticin and its 3''-fluoroanalog have been prepared from easily accessible starting materials. The key step of these syntheses is the silver carbonate-mediated glycosidation reaction employed for the selective formation of a β -glycosidic bond. A palladium acetate-catalyzed Heck-Mizoroki reaction in triethanolamine established an (E) configuration in the stilbene with simultaneous deprotection of the carbohydrate.
- Csuk, Rene,Albert, Sabrina
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experimental part
p. 311 - 316
(2011/05/07)
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- USE OF HYDROXYSTILBENES FOR DYEING, READY-TO-USE COMPOSITION CONTAINING THEM AND DYEING PROCESS
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The invention relates to the use of hydroxystilbenes for dyeing, to ready-to-use dye compositions comprising them, to a dyeing process using them and to a multi-compartment device containing the compositions used in the processes of the invention.
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- Studies on Rhubarb (Rhei Rhizoma). VI. Isolation and Characterization of Stilbenes
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Nineteen stilbene derivatives (I-XIX), of which five are novel cis-stilbenes, have been obtained from a rhubarb of low quality (commercial name:, Imo-Daio).Based on chemical and spectroscopic evidence, these compounds have been characterized as rhapontigenin (I), rhaponticin (II), rhapontigenin 3'-O-β-D-glucopyranoside (III), rhaponticin 6''-O-gallate (IV), rhaponticin 2''-O-gallate (V), rhaponticin 2''-O-p-coumarate (VI), piceatannol (VII), piceatannol 3-O-β-D-glucopyranoside (VIII), piceatannol 3'-O-β-D-glucopyranoside (IX), piceatannol 3'-O-β-D-xylopyranoside (X), piceatannol 3-O-β-D-(6''-O-galloyl) glucopyranoside (XI), desoxyrhaponticin (XII), desoxyrhaponticin 6''-O-gallate (XIII), 3,4',5-trihydroxystilbene 4'-O-β-D-(6''-O-galloyl) glucopyranoside (XIV), cis-3,3',5-trihydroxy-4'-methoxystilbene 3-O-β-D-glucopyranoside (XV), cis-3,3',5-trihydroxy-4'-methoxystilbene 3-O-β-D-(6''-O-galloyl) glucopyranoside (XVI), cis-3,5-dihydroxy-4'-methoxystilbene 3-O-β-D-glucopyranoside (XVII), cis-3,3',5-trihydroxy-4'-methoxystilbene 3-O-β-D-(2''-O-galloyl) glucopyranoside (XVIII) and cis-3,3',5-trihydroxy-4'-methoxystilbene (XIX).Keywords - rhubarb; Polygonaceae; trans-stilbene; cis-stilbene; gallic acid ester; p-coumaric acid ester; rhaponticin; desoxyrhaponticin; piceatannol; 3,4',5-trihydroxystilbene
- Kashiwada, Yoshiki,Nonaka, Gen-ichiro,Nishioka, Itsuo
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p. 3501 - 3517
(2007/10/02)
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