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colour of anthraflavine solutions is deep yellow, or when 
concentrated reddish-yellow. In concentrated sulphuric 
acid isoanthraflavine dissolves with a cherry-red, anthra- 
flavine with a yellow colour. The two substances may also 
be readily distinguished by their behaviour towards lime 
and baryta water, in which isoanthraflavine dissolves easily 
in the cold, yielding red solutions. Anthraflavine, on the 
other hand, is almost insoluble in cold baryta water, and 
only dissolves on boiling, while in lime water it is almost 
insoluble at all temperatures. Isoanthraflavine in most of 
its properties approaches purpuroxanthine even more closely 
than it does to anthroflavine ; but having prepared a speci- 
men of purpuroxanthine according to Schutzenberger’s pro- 
cess, we are enabled to assert positively that the two bodies 
are not identical. One of the characteristic properties of 
purpuroxanthine is that it yields phthalic by oxidation with 
nitric acid, whereas isoanthraflavine gives with nitric acid 
a nitro-substitution product. 
The barium compound of isoanthraflavine can be made to 
crystallise (though not without some difficulty) in dark red 
needles resembling barium anthraflavate. It contains water 
of crystallisation, which it loses on being heated to 150°. 
The composition of the dry salt corresponds with the for- 
mula C 14 H 6 Ba0 4 . 
Tetmbromisoanthmflavine, C 14 H 4 Br 4 0 4 , is prepared in the 
same way as tetrabromanthraflavine. It crystallises in 
yellow needles, soluble in boiling alcohol and in glacial 
acetic acid. 
Diacetyiisoanthraflavine, C 14 H 6 (C 2 H 3 0 ) 2 0 4 was obtained 
by the action of acetic anhydride on isoanthraflavine at 160 
to 180°. It crystallises in light yellow microscopic needles, 
which are soluble in alcohol and more easily soluble in 
glacial acetic acid. At 175° it commences to soften, and at 
about 195° it fuses completely. It is decomposed by alco- 
holic potash solution. 
