525 
_ Van Romporen had already found’) that the principal product of 
the reaction is 1.3.4.6 trinitrodimethylaniline. 
Besides this compound there is also formed in small quantity a 
substance which crystallises from ethyl acetate in beautiful yellow 
erystals. The substance melted with slight decomposition at 132° 
forming a pale yellow liquid. 
At first I was of opinion that I had obtained a new trinitro- 
isomeride, probably the 1.2.3.6 compound. On varying the conditions 
however, with the object of increasing the yield, when a smaller 
quantity of nitric acid was used for the nitration, a rise in tempe- 
rature to 40° C. was observed, and a copious evolution of brown 
fumes took place. I was surprised to find that more of the 
substance had been formed. It occurred to me that the compound 
might be a product of the action of nitrous acid. This assumption 
appeared to be correct. If the 1.3.6 compound is dissolved in dilute 
sulphuric acid (1:1) and sodium nitrite is added, an almost quanti- 
tative yield of the above substance is obtained. On treatment with 
nitric acid (Sp. Gr. 1.4) the substance is transformed into the 
nitrosamine (M.p. 201°) already described. It must therefore be 
considered as the nitrosamine of the 1.3.6 compound. 
In the nitration of the 1.3.6 dinitro-derivative the effect of 
nitrous acid on the reaction velocity is extraordinarily great. By 
the addition of urea it is possible to stop the reaction altogether. 
If the temperature of the reaction is perceptibly higher than room 
temperature the only final product obtained is the substance 
melting at 201°. Both the substance melting at 132° and the 
1.3.4.6 trinitro-derivative are transformed into the above nitrosamine. 
Repeated attempts to obtain an isomeric trinitro-derivative were 
all unsuccessful, the only product obtained being the nitrosamine. 
This research is being continued, and the results will be described 
in greater detail later. 
Bergen op Zoom, June 1919. 
1) These Proceedings, III, 258. 
35 
Proceedings Royal Acad. Amsterdam. Vol XXII. 
