58 
CHEMISTRY: R. N. HARGER 
Proc. N. a. S. 
each molecule of hydroquinol. The colored crystalline compounds formed 
under such conditions are very stable and can be easily purified. The 
compound formed by the oxidation of hydroquinol in the presence of di- 
methylamine melts at 171° and is to be expressed by the formula 
C10H14O2N2. While its constitution has not yet been completely established 
it appears to be identical with tetramethyl diamino-quinone which was 
obtained by Mylius^ by treatment of benzo-quinone with dimethylamine, 
and to which Kehrmann^ has assigned the structural formula: 
Aliphatic derivatives of this type are analogous in constitution to di- 
anilino-quinone which Hofmann^ prepared by interaction of aniHne with 
quinone. While a large number of these anilino-quinones have been syn- 
thesized, an examination of the literature has shown that only four other 
representatives of these aliphatic amino quinones are known : the methyl- 
amino derivatives of toluquinone, ^ 2-5 xyloquinone,^ and thymoquinone,^ 
and the ethylamino derivative of thymoquinone.^ These were prepared 
by interaction of the amine and quinone with yields which were said to be 
very low. The above mentioned oxidation of hydroquinol appears, 
therefore, of special interest as a simple, efficient means of preparing these 
aliphatic amino quinones, which latter compounds seem to present a chem- 
ical field as yet very little developed. 
A somewhat analogous oxidation in the naphthalene series has been 
recorded by Plimpton.^ He prepared amino derivatives of naphthoquinone 
by the action of amines upon naphthoquinone and notes that these com- 
pounds are also produced when a solution of naphthoquinol and the amine 
is exposed to the air. The resulting product, however, was a mono- 
aminoquinone and not a J^-aminoquinone such as we appear to have with 
the benzene series. 
The brilliant purple compounds corresponding to formula I are not the 
only products resulting from this oxidation of hydroquinol and aliphatic 
amines. The yield of these purple compounds never approaches quantita- 
tive values, and on concentrating the filtrate to expel the excess of free 
amine there is deposited, upon cooling, a considerable amount of dark 
yellow crystals indicating at least another compound. This latter is now 
being investigated. It has also been found that when an aliphatic amine 
is added to hydroquinol the first product of reaction is a double compound 
or addition product of the amine and hydroquinol. Several such com- 
O 
/\ 
-N(CH3)2 
O 
