1963 年 83 巻 9 号 p. 897-900
Two kinds of flavonol, yellow needles and pale yellow prisms or needles, were obtained from the methanolic extract of the tree bark of pecan (Carya pecan ENGL. et GRAEBN.). The flavonol forming yellow needles was recrystallized from hydrous methanol into yellow needles, m.p. 317-320°, C16H12O7⋅H2O (acetate, m.p. 197-198°). It has one methoxyl group and potash fusion afforded protocatechuic acid and phloroglucinol. Its decomposition with 50% potassium hydroxide also afforded protocatechuic acid and phloroglucinol monomethyl ether. Methylation with dimethyl sulfate gave quercetin pentamethyl ether and demethylation with hydriodic acid (sp. g. 1.7) gave quercetin. It was easily methylated by diazomethane to form quercetin pentamethyl ether. It showed strong fluorescence by ultraviolet irradiation. From these experimental results, this flavonol was considered to be quercetin monomethyl ether, with methoxyl in 5-position. Quercetin 5-methyl ether had been found in nature and named azaleatin, and the present flavonol from pecan was found to agree well with azaleatin.