343 
isomerides cannot be transformed directly into each other. A 0,1 
normal solution of NaOH causes all the chlorine to be split-off 
from the «-derivative within five hours at 0°C.; the g-derivative, 
however, does not liberate its chlorine under the same circumstances. 
The determinations of carbon, hydrogen, and chlorine (Carius), 
and those of the molecular weight, gave with both substances the 
same results, all agreeing with the composition of a chlorotetracetyl- 
fructose: C,H,O(C,H, O,), Ci. 
$ 2. In connection with the measurements of the isomeric @- and 
B-pentacetyl-*), and tetracetyl-d-fructoses*) formerly made by the 
author, it appeared of interest to study these two isomerides also 
from a crystallographical point of view, and to compare them with 
each other, as well as with the derivatives mentioned above. Chiefly 
with respect to the instability of the a-derivative, it was necessary, 
therefore, to prepare both isomeric substances once more, and imme- 
diately to measure the crystals eventually obtainable under favour- 
able circumstances. This was possible to me by Mr. Braun’s kind 
assistance, who placed a quantity of the 9-tetracetyl-derivative already 
described at my disposal, as well as his notes about the method of 
preparation of the chloro-derivatives. | wish to express to him also 
here my sincere thanks for his interest and help. 
The preparation, especially of the «-compound, must be carefully 
supervised; it is not so easy as it might perhaps appear to be. 
More particularly, the tetracetyl-fructose used must be free from acid, 
and the reagents applied may not contain moisture, nor may appre- 
ciable changes of temperature occur during the reaction. It is desir- 
able to work very rapidly: therefore, the evaporation of the solutions 
must take place under a glass bell-jar connected with a drying 
apparatus by blowing over the surfaces air carefully dried with 
calciumchloride. The e«-compound can best be recrystallized from 
dry ether in the ice-box at 0°C., and in darkness, moisture being 
carefully excluded. The same precautions should be taken in preparing 
the B-isomeride; but the substance may be recrystallized in the usual 
way at roomtemperature. Purification of the 8-compound can best 
be done by recrystallizing it from boiling absolute alcohol; to obtain 
beautiful and measurable crystals, the substance is dissolved in pure 
benzene, or in a mixture of chloroform and benzene, from which 
it is deposited on slow evaporation in big, transparent, prismatic 
1, F. M. JazeeR Proceed. R. Acad. of Sciences, Amsterdam, 20, 280, (1918). 
*) EF. M. Jazcer. Proceed. R. Acad. of Sciences, Amsterdam, 10, 563, (1903); 
Zeits. f. Kryst. und Miner., 45, 539, (1908). 
