246 
CHAS. E. SANDO 
The acetyl derivative forms glistening yellow lath-like crystals which 
probably belong to the triclinic system^. The compound melts with decom- 
position at about 184°-! 86° C. (uncorrected). Hawkins and Stevens give 
1 96°-! 97° C. (uncorrected) as the melting point of a white acetyl derivative 
of endothine red. Repeated efforts to verify their statement^ were not suc- 
cessful, since only the yellow derivative described above resulted in all trials. 
The number of acetyl groups was ascertained by determining the acetic 
acid liberated, and the results were confirmed by determining the yield of 
endothine red recovered on hydrolysis of the diacetyl compound. Three 
methods were followed in estimating the acetic acid liberated on hydrolysis 
of the acetyl derivative. 
The first method^" consisted in boiling the compound in an Erlenmeyer 
flask for several hours with dilute barium hydroxide. The mixture was 
then acidified at ordinary temperature with phosphoric acid and the acetic 
acid distilled off. The distillate was treated with an excess of barium hy- 
droxide, evaporated to a small volume and treated with carbon dioxide. 
The solution was then separated from the excess barium carbonate by filtra- 
tion and the filtrate evaporated to dryness in a platinum dish. The residue 
was taken up in carbon dioxide-free water. The barium in solution was 
determined as sulphate. 
For the second method^^ the acetyl derivative was placed in a flask with 
30 cc. of alcohol and 2 cc. of sulphuric acid. The mixture was subjected to 
distillation until two thirds of the liquid had passed over. Fresh alcohol 
was then added and the operation repeated until the distillate gave no test 
for acetic acid. The distillate was collected in standard alcoholic potash 
which was subsequently heated a few minutes to hydrolyze the ethyl 
acetate formed and finally titrated with standard sulphuric acid. 
In the third method the substance was hydrolyzed with dilute sul- 
phuric acid (75 parts of acid to 32 parts of water) on a hot water bath for 
one half hour, then diluted to 8 volumes and heated on a boiling water 
bath for 3 hours. The whole process was carried out under a reflux con- 
denser. After 24 hours, the insoluble pigment was filtered off, washed with 
a little water, dried, and weighed. The filtrate was subjected to steam 
distillation until about 500 cc. had passed over. The distillate was titrated 
^ The author is indebted to Mr. C. M. Smith, of the Insecticide and Fungicide Board, 
or the examination under the petrographic microscope of endothine red and its diacetyl 
derivative. 
3 In attempting to clarify this point, Dr. Hawkins assured the writer that the acetyl 
derivative described in their paper was obtained in small quantities and may have resulted 
from an impurity present with the pigment. 
10 Herzig, J. Studien iiber Quercetin und seine Derivate. I. Abhandlung. Monats- 
hefte fiir Chemie 5: 72-93. 1884. 
11 Perkin, Arthur George. The determination of acetyl groups. Journ. Chem. Soc. 
(London) Trans. 87: 107-110, 1905. 
^2 Liebermann, C. Ueber einige friiher beschriebene Derivate des Quercetins. Ber. 
Deutsch. Chem. Ges. 17: 1680-1684. 1884. 
