treatment of 5,8-dihydroxy-1-tetralone (9) with either 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (ddq) in refluxing benzene or silver (i) oxide in refluxing 1,4-dioxane afforded juglone (5-hydroxy-1,4-naphthoquinone) (1) in good yield. with manganese dioxide in dioxane the tetralone gave a mixture of juglone and naphthazarin (5,8-dihydroxy-1,4-naphthoquinone) (3), the proportion of naphthazarin...

Treatment of 5,8-dihydroxy-1-tetralone (9) with either 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in refluxing benzene or silver (I) oxide in refluxing 1,4-dioxane afforded juglone (5-hydroxy-1,4-naphthoquinone) (1) in good yield. With manganese dioxide in dioxane the tetralone gave a mixture of juglone and naphthazarin (5,8-dihydroxy-1,4-naphthoquinone) (3), the proportion of naphthazarin...

The structure of 7,8-dihydroxy-4-methylcoumarin was determined by an X-ray diffraction method. The compound crystallized in the triclinic space group P1, Z = 2, with a = 7.631(2), b = 9.456(5), c = 7.075(3)A, alpha = 103.13(3), beta = 91.84(3), gamma= 68.21(3) degrees, and V= 460.9(3)A3. The X-ray crystal structure was also compared with those of 5,7-dihydroxy-4-methylcoumarin and 7-hydroxy-4-m...

Five new flavonoids, 5,8-dihydroxy-3,7-dimethoxy-3',4'-methylenedioxyflavone (1), 7-hydroxy-3,5-dimethoxy-3',4'-methylenedioxyflavone (2), 7-(2,3-dihydroxy-3-methylbutoxy)-3,5-dimethoxy-3',4'-methylenedioxyflavone (3), 7-(2,3-dihydroxy-3-methylbutoxy)-3,3',4',5-tetramethoxyflavone (4), and 7-(2,3-dihydroxy-3-methylbutoxy)-3,3',4',5,8-pentamethoxyflavone (5), were isolated from the leaves of Mel...