1964 年 84 巻 11 号 p. 1119-1123
It was found that a certain kind of flavone derivatives reacted with Sr2+ to produce yellow, brown to black precipitation in ammoniacal methanol solution, and that the reaction was more sensitive than usual Mg+HCl reaction. In order to investigate the precipitation reaction, six kinds of methylated quercetin derivatives, whose five hydroxyl groups being totally or partially methylated, were studied with Sr2+ for its precipitation formation. The result was that 3, 5, 7, 3′, 4′-pentamethoxyflavone, 5-hydroxy-3, 3′, 4′, 7-tetramethoxyflavone, 3-hydroxy-3′, 4′, 5, 7-tetramethoxyflavone, 3, 4′5, 7-tetrahydroxy-3′-methoxyflavone, were found to be negative with Sr2+. However, 3, 4′, 5, 7-tetrahydroxy-3′-methoxyflavone and 3′, 4′, 5-trihydroxy-3, 7-dimethoxyflavone showed positive reaction. On the reaction products with quercetin and 3, 4′, 5-trihydroxy-3, 7-dimethoxyflavone, the Sr contents were determined quantitatively and the binding molar ratio of flavone derivatives and Sr was found to be 1:1. Therefore, the hydroxyl groups at 3′- and 4′-position of flavone derivatives were considered to participate in the precipitation reaction with Sr2+.