Mr Crocker , On the formation of Di-nitro-phenoxazines. 345 
extremely soluble, and alcohol added to the solution, a chocolate- 
brown crystalline precipitate was formed. These crystals contained 
aniline, and when heated evolved aniline and then exploded. The 
high melting-point (269°) suggested that condensation of the 
phenol-body to the oxazine had taken place and this was proved 
by the abundant presence of nitrite in the aniline liquors. More- 
over, alcoholic potash gave no coloration in the cold, but when 
heated the blue-violet of the oxazines was immediately apparent. 
Owing to their extreme solubility in aniline, and the necessity 
for using alcohol as precipitant, these crystals were not obtained 
quite pure. The aniline found approached most nearly to two 
molecules of aniline of crystallisation. After evaporation of the 
aniline, the residual brown powder was crystallised from dilute 
acetic acid. It was then obtained as a dark-bronze powder, m.p. 
277°. Analysis gave results in accordance with picramido-di- 
nitro-phenoxazine. 
*2115 gm. gave 37 0 c.c. N at 18*5° and 751 bar. pr. 
/NH . Pi 
C, ; H ;i -NH \ c , ;H/N02)5 
Nitrogen 20'04 19’68 
Attempts to get the oxazine direct from amidol only resulted 
in a small yield of oxazine, which deposited first, and a good yield 
of the phenol-body. Excess of KOH should be carefully avoided. 
The use of alkaline sulphite in place of alkali makes the process 
simpler and gives an excellent product, but the yield of the phenol- 
body is not so good. It was not found possible to condense the 
phenol-body by the use of strong alkalis like potash. Feebly 
alkaline bodies, e.g. aniline or sodium phosphate, on the other 
hand, usually cause the oxazine condensation. The following 
method gave satisfactory results. 
4 gm. of the phenol-body were added to 350 c.c. alcohol and 
heated on water-bath. 46 gm. of pulverised sodium phosphate 
were gradually added while stirring. The substance dissolved 
and minute bronze sheeny plates immediately settled out. The 
substance, recrystallised from glacial acetic, consisted of minute 
bronze-coloured plates, melting at 277°, which give the character- 
istic oxazine reaction with potash. It was difficultly soluble in 
alcohol, and fairly easily soluble in glacial acetic acid. The yield 
of crude product was 3*5 gm. Analysis gave results in accordance 
with picramido-di-nitro-phenoxazine 
^NH . Pi 
