From Wikipedia,
the free encyclopedia.
Indulines are a series
of
dyestuffs of blue, bluish-red
or black shades, formed by the
interaction of para-amino
azo compounds with primary
monamines in the presence of a
small quantity of a
mineral acid. They were first
discovered in
1863 by J. Dale and H. Caro,
and since then have been examined
by many
chemists.
They are derivatives of the
eurhodines (aminophenazines,
aminonaphthophenazines), and by
means of their diazo derivatives
can be de-amidated, yielding in
this way azonium
salts; consequently they may
be considered as amidated azonium
salts. The first reaction giving a
clue to their constitution was the
isolation of the intermediate
azophenin by O. Witt, which was
proved by Fischer and Hepp to be
dianilidoquinone dianil, a similar
intermediate compound being found
shortly afterwards in the
naphthalene series. Azophenin,
C30H24N4,
is prepared by warming quinone
dianil with
aniline; by melting together
quinone, aniline and aniline
hydrochloride; or by the
action of aniline on
para-nitrosophenol or
para-nitrosodiphenylamine. The
indulines are prepared as
mentioned above from aminoazo
compounds, or by condensing oxy-
and amido-quinones with phenylated
ortho-diamines. The indulines may
be subdivided into the following
groups: (1) benzindulines,
derivatives of phenazine; (2)
isorosindulines; and (3)
rosindulines, both derived from
naphthophenazine; and (4)
naphthindulines, derived from
naphthazine.
The rosindulines and
naphthindulines have a strongly
basic character, and their
salts possess a marked red
color and
fluorescence. Benzinduline (aposafranine),
C16H13N3,
is a strong base, but cannot be
diazotized, unless it be dissolved
in concentrated
mineral acids. When warmed
with aniline it yields
anilido-aposafranine, which may
also be obtained by the direct
oxidation of
ortho-aminodiphenylamine.
Isorosinduline is obtained from
quinone dichlorimide and
phenyl-13-naphthylamine;
rosinduline from
benzeneazo-a-naphthylamine and
aniline and naphthinduline from
benzeneazo-a-naphthylamine and
naphthylamine.
This article incorporates
text from the
1911 Encyclopędia
Britannica, which is in the
public domain.
