The Manufacture or Production of New Indoxyl Derivatives.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Communicated from abroad by THE FARBENFABRIKEN vormals FRIEDRICH BAYER
& Co., of Elberfeld, Germany.
The Manufacture or Production of New Indoxyl Derivatives.
I, HENRY EDWARD NEWTON, of the Office for Patents, 6, Bream's Buildings,
Chancery Lane, in the County of London, Patent Agent, do hereby declare the nature
of this invention to be as follows:-
In the Specification of Letters Patent No. 62113, my foreign correspondents
described the production of a diacetyl derivative of indoxyl, having most probably
the formula ·
My foreign correspondents have now found that the acetylic group (I.) which is
bound to the oxygen atom, can be split off much more easily by the action of saponi-
fying agents than that acetylic group (II.) which is bound to the nitrogen. My
foreign correspondents have further succeeded in finding a saponifying process by
means of which it is possible to split off-the acetylic group I. exclusively, monoacetyl
indoxyl of the formula :-

page_text: employing sodium bisulphite, sodium sulphite, sodium phosphate, or the like agents,
acting in the same or in a similar manner.
The new process may be illustrated by the following example, the parts being by
weight.
EXAMPLE.
A mixture prepared from 10 parts of diacetyl indoxyl and 15 parts of sodium
sulphite, which have been dissolved in 200 parts of water, is heated at about
70 degrees Centigrade while being continuously stirred. By means of this operation,
the diacetyl indoxyl is by-and-by dissolved, whilst the monoacetyl-indoxyl begins to
separate in the shape of glittering needles. When the precipitate thus obtained no
longer increases, the liquid is allowed to cool, the monoacetyl indoxyl which is
difficultly soluble in cold water, being separated in a pure state.
The new body thus obtained melts at 135 degrees Centigrade. It is easily soluble
in boiling water, in alcohol, and in a cold diluted caustic soda-lye. On heating the
caustic alkaline solution, or on allowing the same to stand for a time, the monoacetyl
indoxyl is entirely saponified, indoxyl being produced.
The process proceeds in an analogous manner if, instead of diacetyl indoxyl, its
derivatives are used.
The monoacetyl-indoxyl compounds may be profitably employed for the production
of indigo or its derivatives on fibre.
Of course my foreign correspondents do not limit themselves to the particulars
given in the above example, as this is merely typical.
2011
Tl 1900
NEWTON & SON,
Agents for the Applicant.
I, HENRY EDWARD NEWTON, of the Office for Patents, 6, Bream's Buildings,
Chancery Lane, in the County of London, Patent Agent, do hereby declare the
nature of this invention and in what manner the same is to be performed, to be 3
particularly described and ascertained in and by the following statement:-
In the Specification of Letters Patent No. 52118, my foreign correspondents
described the production of a diacetyl derivative of indoxyl, having most probably
the formula.
My foreign correspondents have now found that the acetylic group (I.), which is
bound to the oxygen atom, can be split off much more easily by the action of
saponifying agents than that acetylic group (II.) which is bound to the nitrogen.
My foreign correspondents have further succeeded in finding a saponifying process

page_text: by means of which it is possible to split off the acetylic group I. exclusively,
monoacetyl indoxyl of the formula:
(which was unknown up to the present time) being produced.
According to the researches of my foreign correspondents, this result is obtaine.l
by using such saponifying agents as act in a moderate manner; such, for instance,
as sodium bisulphite, sodium sulphite, sodium phosphate, or the like agents, acting
in the same or in a similar inanner.
The new process may be illustrated by the following example, the parts being
by weight :-
EXAMPLE.
A mixture prepared from 10 parts of carefully pulverized diacetyl indoxyl aud
15 parts of sodium sulphite, which have been dissolved in 200 parts of water, is
heated to about 70 degrees Centigrade while being continuously stirred. By means
of this operation, the diacetyl indoxyl becomes dissolved, whilst the mono-acetyl-
indoxyl separates in the shape of glittering needles. When precipitation stops, the
liquid is allowed to cool, and the monoacetyl-indoxyl, which is not readily soluble
in cold water, is obtained in a pure state.
The new body thus obtained melts at 135 degrees Centigrade. It is easily soluble
in boiling water, in alcohol, and in a cold diluted caustic soda lye. On heating the
caustic alkaline solution, or on allowing the same to stand for a time, the mono-
acetyl indoxyl is entirely saponified, indoxyl being produced.
The process proceeds in an analogous manner if, instead of diacetyl indoxyl, its
derivatives are used.
The monoacetyl indoxyl compounds may be profitably employed for the production
of indigo or its derivatives, on fibre.
Of course my foreign correspondents do not limit themselves to the particulars
given in the above example, as this is merely typical.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me from
abroad, I declare that what I claim is :-
1. The process for the production of monoacetyl-indoxyl or its derivatives, which
process consists in treating diacetyl-indoxyl, or its derivatives, with such saponifying
agents as act in a moderate manner, such, for instance, as sodium bisulphite, sodium
sulphite, sodium phosphate, or the like agents acting in the same or in a similar
manner, substantially as herein before described.
2. As new articles of manufacture, the monoacetyl-indoxyl compounds obtainable
by the process, hereinbefore described and claimed.