Wakeman—Pigments of Flowering Plants. 851 
of Ailanthus glandulosa, also in the leaves of Rhus rhodaw- 
thema 31 
Pure quercetin presents the appearance of a lemon yellow 
crystalline powder made up of tiny needle like crystals. It is 
almost insoluble in cold water, soluble in alcohol, very difficultly 
soluble in ether, and easily soluble in dilute alkalies. It crystal¬ 
lizes with three molecules of water of crystallization which it 
loses at 130°. In alcoholic solution it gives a dark green coloration 
with ferric chloride which turns black upon heating. With 
lead acetate it gives a red precipitate. It reduces silver solu¬ 
tions when cold and Fehling’s solution when heated. Quercetin 
melts at 250°. When treated with chromic acid and acetic acid 
it is oxidized to quercetone. 
To fabrics mordanted with aluminum quercetin imparts a 
brownish yellow color; with chromium, a deep orange color; 
with iron, a dark olive; and with tin, a bright orange yellow. 
Quercetone . 
Quercetone, 32 the oxidation product of quercetin, crystallizes 
in small deep red needle like crystals which melt above 360°. 
It dissolves in alkalies with a blue, and in concentrated sul¬ 
phuric acid with a red coloration. When heated with acetic 
acid and zinc dust acetylated hydroxy quercetin is obtained as 
a colorless, amorphous powder which yields upon hydrolysis 
penthydroxy-1, 3, 4, 3', 4 , -flavonol. This crystallizes in small 
yellow needles which lose a molecule of water at 160°, and melt 
at 352°-355°. Both alkaline hydroxides and sulphuric acid 
dissolve it with a yellow color. Pentmethoxy flavonol forms, 
small colorless crystals which melt at 147°-149°. 
31 Jr. Chem. Soc., 73, p. 1017. 
32 Ber., 44, p. 3487. 
