- FLAVONOIDS FROM ARTEMISIA LANATA
-
A new flavonoid, gossypetin-7,8,3',4'-tetramethyl ether (3,5-dihydroxy-7,8,3',4'-tetramethoxyflavone) was isolated and its structure elucidated by chemical and spectroscopic methods.The known flavonoids 5-hydroxy-6,7,3',4'-tetramethoxyflavone and artemeti
- a D.,Collado, I. Gonzales,Macias, F. A.,Massanet, G. M.,Luis, Rodriguez F.
-
-
Read Online
- INTERNAL AND EXTERNAL LEAF FLAVONOIDS OF PERICOME CAUDATA
-
Pericome caudata accumulates four flavonol aglycones externally on leaf and stem surfaces.The glycosides present in the leaf tissue are based on eight further flavonols.This preponderance of tissue flavonoids over exudate flavonoids is unusual.Key Word In
- Wollenweber, Eckhard,Mann, Karin
-
-
Read Online
- STUDIES OF THE SELECTIVE O-ALKYLATION AND DEALKYLATION OF FLAVONOIDS. XII. A NEW, CONVENIENT METHOD FOR SYNTHESIZING 3,5-DIHYDROXY-6,7-DIMETHOXYFLAVONES FROM 3,5,6,7-TETRAMETHOXYFLAVONES
-
The 5-methoxy group on 3,5,6,7-tetramethoxyflavones and the 3-methoxy group on 3,6,7-trimethoxy-5-tosyloxy-flavones were selectively cleaved with anhydrous aluminum bromide in acetonitrile under controlled conditions without the cleavage of benzyloxy groups on the B ring.By the application of these reactions, seven 3,5-dihydroxy-6,7-dimethoxyflavones were easily synthesized from the corresponding 3,5,6,7-tetramethoxyflavones which were synthesized from 3,6-dihydroxy-2,4ω-trimethoxycetophenone by means of the Allan-Robinson reaction followed by methylation.Keywords: Allan-Robinson reaction ; selective demethylation; 3,5,6,7-tetramethoxyflavone; 5-hydroxy-3,6,7-trimethoxyflavone; 6-hydroxy-3,5,7-trimethoxyflavone; 5-tosyloxyflavone; 5,6-dihydroxy-3,7-dimethoxyflavone; 3,5-dihydroxy-6,7-dimethoxyflavone, 3,5-diacetoxy-6,7-dimethoxyflavone
- Horie, Tokunaru,Kawamura, Yasuhiko,Tsukayama, Masao,Yoshizaki, Shiro
-
p. 1216 - 1220
(2007/10/02)
-