Wakeman—Pigments of Flowering Plants. 
845 
Chevruel 1 probably first extracted fisetin in the form of a tan¬ 
nin; though perhaps impure, from the fustel wood. Some 
years later it was again obtained from the same source by 
Bolley. 2 It was later isolated and studied by Schmidt, 3 Her- 
zig, 4 Perkin, 5 and Kostanecki. 6 
Our ideas of the constitution of fisetin are based upon the 
work of Hirzig who showed that by boiling with alcoholic po¬ 
tassium hydroxide fisetin did not yield phloroglucin, but fisetol 
and protocatechuic acid, with traces of resorcin. By the syn¬ 
thesis of fisetol (ethylresorcylic acid), Kostanecki and Tambor 
confirmed the work of Herzig. 
coc 2 h. 
c 
coo H 
Fisetol. 
Fisetin occurs as a glucoside in Rhus cotinus, 7 Rhus rhodan- 
thema 8 and Querbracho Colorado . 9 It also occurs free in Rhus 
rhodanthema, 10 and in the blossoms of Butea frondosa. 11 
Crystallized from dilute alcohol fisetin forms small lemon 
yellow needle like crystals. From acetic acid it crystallizes in 
yellow prisms with six molecules of water of crystallization. 
Fisetin is almost insoluble in water, easily soluble in alcohol, 
acetone and acetic acid. It is difficultly soluble in ether, ben¬ 
zene, petroleum ether and chloroform. Ferric chloride when 
added to fisetin solutions produces a dark green coloration and 
1 Zeit. anal. Chem., 12, p. 127. 
3 Bull. Soc. Chim., 2, p. 479. 
8 Ber., 19, p. 1734. 
4 Monatsh., 12, p. 177. 
5 Jr. Chem. Soc., 67, p. 648; 69, p. 1304. 
6 Ber., 28, p. 2302; 37, p. 784; 38, p. 3587. 
1 Ber., 19, p. 1703. 
8 Jr. Chem. Soc., 71, p. 1194. 
9 Chem. News, 74, p. 120. 
10 Jr. Chem. Soc., 71, p. 1194. 
11 Proc. Chem. Soc., 19, p. 183; Jr. Chem. Soc., 85, p. 1459. 
