Studies of the Selective<i>O</i>-Alkylation and Dealkylation of Flavonoids. XV. A Convenient Synthesis of 3,5,6-Trihydroxy-7-methoxyflavones and Revised Structures of Two Natural Flavones
作者:Hideaki Tominaga、Tokunaru Horie
DOI:10.1246/bcsj.66.2668
日期:1993.9
tosylate of the 5-hydroxyflavone was selectively cleaved with anhydrous aluminum bromide in acetonitrile to give 6-acetoxy-3-hydroxy-4′,7-dimethoxy-5-(tosyloxy)flavone. 3,6-Dihydroxy-4′,7-dimethoxy-5-(tosyloxy)flavone, a deacetylated product of the flavone, was easily hydrolyzed to the desired 3,5,6-trihydroxy-4′,7-dimethoxyflavone in high yield via the corresponding 6-methoxymethyl ether. Eight 3,5,6-tri
6-羟基-3,4',5,7-四甲氧基-和5,6-二羟基-3,4',7-三甲氧基黄酮的混合物被转化为6-乙酰氧基-5-羟基-3,4',7 -三甲氧基黄酮通过乙酰化和随后的脱烷基化。5-羟基黄酮甲苯磺酸酯中的 3-甲氧基在乙腈中用无水溴化铝选择性裂解,得到 6-乙酰氧基-3-羟基-4',7-二甲氧基-5-(甲苯磺酰氧基)黄酮。3,6-二羟基-4',7-二甲氧基-5-(甲苯磺酰氧基)黄酮是黄酮的脱乙酰产物,很容易以高产率水解为所需的3,5,6-三羟基-4',7-二甲氧基黄酮通过相应的6-甲氧基甲基醚。用该方法合成了8个3,5,6-三羟基-7-甲氧基黄酮并阐明了它们的性质。此外,两个 3,5,