( 891 ) 
obtained, besides the monomethyl derivative, a quantity of 2.4 
dinitropbenylmethylnitrosamine. 
That, in conjunetion with the results of the nitration experi- 
ment in the presence of urea, we may explain the reaction in this 
way, viz. that first of all the nitrated dimethyl compound is generated, 
and that this is then converted by the nitrous acid (which is formed 
by the oxidising action of the nitric acid) into the monomethyl 
compound (or the nitroso derivative, respectively) is very probable, 
but by no means certain. Experiments are still in progress to establish 
this. In the meantime, I have studied the action of nitrous acid on 
some of the dialkyl derivatives of dinitroanilines. 
If we dissolve 2.4 dinitrodimethylaniline in 5 times its weight of 
nitric acid (D. 1.3) and then add to that solution sodium nitrite until 
it acquires a strong odour of nitrous acid, a pale yellow compound 
erystallises, which melts at 86°") and is identical with the 2.4 dinitro- 
phenylmethylnitrosamine prepared according to _STOERMER*). On 
boiling with acetic acid, the nitrogroup is replaced by hydrogen and 
we obtain the 2.4 dinitromonomethylaniline (m.p. 176°). With 2 4- 
dinitrodiethylaniline the reaction proceeds in quite an analogous 
manner. 2.4 dinitrophenylethylnitrosamine*) (m.p. 52) is formed 
which also readily loses NO by boiling with acetic acid, and yields 
2.4 dinitroethylaniline (m.p. 414°). 
2.4 dinitrodipropylaniline®) is also converted by nitrous acid into 
a nitroso compound from which, by means of boiling acetic acid, 
the dinitromonopropylaniline (m.p. 97°) may be again obtained. 
In the dialkyl derivatives of 3.4-dinitroaniline an alkyl group is also 
eliminated by nitrous acid. If, however, we carry out the reaction 
in a nitric acid solution (D. 1.3) it is accompanied by a further 
nitration because, as it seems, the nitrous acid accelerates the nitrating 
action of the dilute nitric acid. 
If, however, we work in a sulphuric acid solution (1 vol. of acid, 
1 vol. of water) a nitrosomonoalkyl compound is formed even with 
these derivatives. 
With 3.4-dinitrodiethylaniline, for instance, a beautiful pale yellow 
nitroso derivative (m. p. 79°—80°) is formed from which the nitroso 
1) It is sometimes contaminated with the non-nitrosated monomethyl compound. 
It will be ascertained whether this is formed primarily, or by the action of the 
nitric acid on the nitroso compound. (Compare STOERMER loc. cit. 
2) B. 81, 2530 [1893]. 
*) STOERMER loc. cit. pag. 2531. 
4) This compound which | described fully 20 years ago (Rec. 8 
is described in Hanrzscn’s paper loc. cit, p. 1675 as a new one. 
252 [1889]), 
? 
