The more complex phenazines, such as the naphthophenazines, naphthazines and naphthotolazines, may be prepared by condensing ortho-diamines with ortho-quinones (0.
Certain a-diketones condense to form benzenoid quinones, two molecules of the diketone taking part in the reaction; thus diacetyl, CH 3 CO CO CH 3, yields p-xyloquinone, C 6 H 2 (CH 3) 2 0 2 (Ber., 1888, 21, p. 1411), and acetylpropionyl, CH 3 CO CO C 2 H 5, yields duroquinone, or tetramethylquinone, C 6 (CH 3) 4 0 2, Oxymethylene compounds, characterized by the grouping > C:CH(OH), also give benzene derivatives by hydrolytic condensation between three molecules; thus oxymethylene acetone, or formyl acetone, CH 3 CO.
Aminoand oxy-benzenes, aminophenols, quinones, and oxycarboxylic acids.
This assumed that all coloured substances were derivatives of orthoor para-quinone (see Quinones), and although at the time of its promotion little practical proof was given, yet the theory found wide acceptance on account of the researches of many other chemists.
When treated with hydrochloric acid and potassium chlorate, no chlorinated quinones are obtained (M.
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