Il6 CHAS. E. SANDO AND H. H. BARTLETT 
the yellow color. The data for the combustions of fisetin follow in 
Table II. 
Table II 
Combustions of Fisetin, Recovered from Acetyl Fisetin 
Sample A from wood of Rhus typhina, sample B from wood of R. giabra. 
Sample 
Weight 
CO2 
H2O 
C.fo 
0,fo 
A 
.1074 
.2482 
•0350 
63.02 
3-64 
33-34 
B 
.2550 
.5870 
.0796 
62.78 
3-49 
33 73 
Required for fisetin, CisHioOe 
62.94 
349 
33-57 
The cleavage products of fisetin were determined in the usual way 
by potash fusion. The material was heated thirty minutes at 170- 
200° C. with potassium hydroxide and a very small amount of water. 
The melt was dissolved in water, neutralized with hydrochloric acid, 
and shaken with ether. The residue after evaporating the etherial 
solution was neutralized with sodium bicarbonate and again shaken 
with ether. 
The ethereal layer contained resorcinol, identified as uch after 
purification by sublimation between watch glasses. It was easily 
soluble in water, gave a violet color with ferric chloride, and melted 
at 106-108° C. (uncorrected). Rosenthaler (Der Nachweis organ- 
ischer Verbindungen) accepts the value 110-111°, but quotes 118° as 
E. Schmidt's determination of the melting point of the absolutely 
pure compound. In some of the text-books {e. g., Richter) the melt- 
ing point is given as 118°. Landolt-Bornstein gives it as 111.6°, 
and this value is undoubtedly correct, being taken from a recent deter- 
mination (191 1) of Timmermans. Perkin and Gunnell^ found that a 
Kahlbaum preparation melted at 108-109° C. With this value ours 
is in excellent agreement. 
The sodium carbonate solution, after the removal of the resorcinol, 
was acidified and shaken out with ether. The latter removed a sub- 
stance shown to be protocatechuic acid. It decomposed on heating, 
yielding a sublimate of catechol, identified as such by its melting point 
and reaction with ferric chloride (a green color, passing to violet, then 
red, upon addition of sodium bicarbonate). 
There can be no doubt, therefore, that fisetin is the wood flavone 
of both Rhus typhina and R. glabra. 
8 Perkin, A. G.,and Gunnell, O. The colouring matter of Quebracho Colorado. 
Journ. Chem, Soc. (London), Trans. 69: 1 303-1 309. 1896. 
