STUDIES OF THE SELECTIVE O-ALKYLATION AND DEALKYLATION OF FLAVONOIDS .18. A CONVENIENT METHOD FOR SYNTHESIZING 3,5,6,7-TETRAHYDROXYFLAVONES

被引:21
作者
HORIE, T
KOBAYASHI, T
KAWAMURA, Y
YOSHIDA, I
TOMINAGA, H
YAMASHITA, K
机构
[1] Dept. Chemical Science/Technology, Faculty of Engineering, University of Tokushima, Tokushima 770, Minamijosanjima-cho
关键词
D O I
10.1246/bcsj.68.2033
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
In the demethylation of 6-hydroxy-3,4',7-trimethoxy-5-(tosyloxy)flavone with anhydrous aluminum bromide, the 5-tosyloxyl group was eliminated with bromination to give 8-bromo-3,6,7-trihydroxy-4'-methoxyflavone as the main product. When anhydrous aluminum chloride was used in the demethylation of the acetate, the 5-tosyloxyl group was cleaved prior to the demethylation to give 5,6,7-trihydroxy-3,4'-dimethoxyflavone. Demethylation of 6-hydroxy-4',5,7-trimethoxy-3-(tosyloxy)flavone and its acetate with the bromide or chloride afforded the 5,6,7-trihydroxyflavone without the cleavage of the 3-tosyloxyl group, but was not suitable for the general synthesis of the 3,5,6,7-tetrahydroxyflavones because of the difficulty in removing the protecting group. Consequently, it was found that the direct demethylation of 3,6-dihydroxy-5,7-dimethoxyflavones with anhydrous aluminum chloride-sodium iodide in acetonitrile was the most useful general method for synthesizing 3,5,6,7-tetrahydroxyflavones. Additionally, the reported structures of two natural flavones were revised.
引用
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页码:2033 / 2041
页数:9
相关论文
共 23 条
[1]   EPOXIDATION OF FLAVONES BY DIMETHYLDIOXIRANE [J].
ADAM, W ;
GOLSCH, D ;
HADJIARAPOGLOU, L ;
PATONAY, T .
JOURNAL OF ORGANIC CHEMISTRY, 1991, 56 (26) :7292-7297
[2]   ANCHIMERICALLY ASSISTED DEMETHYLATION OF METHYL ETHERS IN INOSITOL DERIVATIVES WITH AN ALCL3-NAI SYSTEM [J].
AKIYAMA, T ;
TAKECHI, N ;
SHIMA, H ;
OZAKI, S .
CHEMISTRY LETTERS, 1990, (10) :1881-1884
[3]   QUERCETAGETIN 5-METHYL ETHER FROM THE PETALS OF TAGETES-PATULA [J].
BHARDWAJ, DK ;
BISHT, MS ;
UAIN, SC ;
MEHTA, CK ;
SHARMA, GC .
PHYTOCHEMISTRY, 1980, 19 (04) :713-714
[4]   FLAVONOIDS OF BALSAMORHIZA-DELTOIDEA AND WYETHIA-MOLLIS [J].
BOHM, BA ;
CHOY, JB .
BIOCHEMICAL SYSTEMATICS AND ECOLOGY, 1987, 15 (05) :541-543
[5]  
FUKUI K, 1969, NIPPON KAGAKU ZASSHI, V90, P1270
[6]   CHEMOSYSTEMATICS OF COMPOSITAE - FLAVONOID PATTERNS IN CHRYSANTHEMUM COMPLEX OF TRIBE ANTHEMIDEAE [J].
HARBORNE, JB ;
HEYWOOD, VH ;
SALEH, NAM .
PHYTOCHEMISTRY, 1970, 9 (09) :2011-&
[7]   STUDIES OF THE SELECTIVE O-ALKYLATION AND DEALKYLATION OF FLAVONOIDS .13. AN IMPROVED METHOD FOR SYNTHESIZING 5,6,7-TRIHYDROXYFLAVONES FROM 6-HYDROXY-5,7-DIMETHOXYFLAVONES [J].
HORIE, T ;
TOMINAGA, H ;
KAWAMURA, Y ;
YAMADA, T .
JOURNAL OF ORGANIC CHEMISTRY, 1992, 57 (12) :3343-3347
[9]   STUDIES OF THE SELECTIVE O-ALKYLATION AND DEALKYLATION OF FLAVONOIDS .6. DEMETHYLATION OF 8-HYDROXY-5,7-DIMETHOXYFLAVONES WITH ANHYDROUS ALUMINUM-CHLORIDE OR BROMIDE IN ACETONITRILE [J].
HORIE, T ;
KOURAI, H ;
FUJITA, N .
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, 1983, 56 (12) :3773-3780
[10]  
HORIE T, 1986, CHEM PHARM BULL, V34, P30