567 
hours in a press bottle in a water-bath. After cooling, the original 
compound crystallized. Also after heating with alcoholic solutions 
of methyl-, dimethyl- and ethyl-amine I could not state that the nitro- 
group had been acted upon. 
Aniline also, which does act on the 2.3.5-trinitro-methyl-p-toluidine, 
did not act on the 2.3-dinitro-dimethyl-p-toluidine. Nor could amines 
act on the nitro-group of the 2.3 dinitro-mono-methyl-p-toluidine. 
Thus the nitro-group (2) proves to be very closely united with 
the nucleus. Sommer supposed this difficult substitution to be caused 
by “steric hindrance” by the neighbouring methyl-group. 
In order to examine this I heated 0.5 gram of 2.3-dinitro-aniline 
with 5 c.c. of alcohol and 5 c.c. of ammonia (D. 0.91) for one hour 
in a press bottle in a water-bath. The compound proved unchanged. 
From all those experiments it appears again that to define the | 
structure, the rule of LAUBENHEIMER is only to be used with great reserve. 
Nitro-derivatives of diethyl-p-toluidine. 
1 got 2-nitro-diethyl-p-toluidine according to ALFTHAN’s method *). 
If the nitrating liquid is poured out into a large quantity of iced 
water, so that the temperature remains below 25°, then nothing else 
separates but the mono-nitro-product, a red oil (b. p. 195° at 17 m.m.), 
even when a large surplus of nitric acid has been used. ALFTHAN, 
who also obtained higher nitrated products by this reaction, evidently 
had not kept the temperature low while pouring out into iced water. 
When 2-nitro-diethyl-p-toluidine is boiled for some time with conc. 
nitrie acid, then it changes into 9.3.5-trinitro-tolyl-ethy!-nitramine 
(m. p. 98°), a light yellow substance already described by ALrPTHAN, 
More easily is this nitramine to be obtained by nitrating mono- 
ethyl-p-toluidine, dissolved in conc. sulphuric acid at low tempera- 
ture with a large quantity of cone. nitric acid *). 
While keeping the temperature below 0° I dropped 8 c.c. of 
nitrie acid (D. 1.49) dissolved in 20 c.c. of sulphuric acid into 10 c.c. 
of ethyl-p-toluidine dissolved in 110 c.c. of the same acid (D. 1.84). 
After some time I slowly added 100 c.c. of nitric acid (D. 1.49) 
— continually cooling the mass — and then left the liquid in a 
basin of water till next day. On pouring it oui into ice the 2.3.5- 
trinitro-tolyl-ethyl-nitramine precipitated. 
When this substance is boiled for six hours with phenol, amy! 
1) These, Genève (1909). 
2) Van RompurcH & Scuepers, Proc. Roy. Akad. Amst. 369 (1918), 
