The pale yellow crystals obtained from the tree bark of pecan (
Carya pecan ENGL. et GRAEBN.) formed needle crystals of m.p. 299-301° from hydrous methanol and corresponded to C
17H
14O
7⋅3H
2O. When recrystallized from dehyd. methanol, the product formed prismatic crystals of m.p. 299-301°, corresponding to C
17H
14O
7⋅CH
3OH. This substance colors dark green with ferric chloride, deep scarlet with magnesium and hydrochloric acid, is soluble in potassium hydroxide, sodium hydroxide, and sodium carbonate solution, and insoluble in sodium hydrogencarbonate solution. UV λ
maxEtOHmμ (logε): 253 (4.39), 347 (4.37). Acetate, m.p. 141-142°, C
17H
11O
7(COCH
3)
3. It has two methoxyl groups. It shows strong fluorescent on irradiation of ultraviolet rays.
Demethylation of this substance with hydrogen iodide (sp. gr. 1.7) gave quercetin, m.p. 313°, and methylation with dimethyl sulfate gave quercetin pentamethyl ether, m.p. 149-150°, which is also formed on methylation with diazomethane.
Reduction with sodium amalgam followed by acidification with hydrochloric acid produces a scarlet color. It is negative to the “zirconium-citric acid test.” The absorption maximum of its ultraviolet spectrum does not show any marked change in the presence of aluminum chloride. These evidences suggested that the substance is quercetin 3, 5-dimethyl ether and the fact was proved by the formation of protocatechuic acid and phloroglucinol monomethyl ether by decomposition with potassium hydroxide solution, protocatechuic acid and 4, 6-dihydroxy-2, ω-dimethoxy-acetophenone, m.p. 207°, by decomposition with alcoholic potassium hydroxide solution, and substance corresponding to protocatechuic acid diethyl ether and 6-hydroxy-4-ethoxy-2, ω-dimethoxy-acetophenone, m.p. 109-110°, by decomposition of its ethyl ether, C
17H
11O
4(OC
3H
5)
3 (anhyhrate, m.p. 123-124°) with alcoholic potassium hydroxide. This flavonol is a new substance and was named caryatin.
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