IMPROVEMENTS IN PREPARING OXYCHINOLINES.
Year: 1881

page_text: LETTERS PATENT to Zdenko Hans Skraup, Doctor of Philosophy and
Lecturer of Chemistry in the University of Vienna. Empire of Austria for
an Invention of IMPROVEMENTS IN PREPARING OXYCHINOLINES.
PROVISIONAL SPECIFICATION left by the said. Zdenko Hans Skraup at
the Office of the Commissioners of Patents on the 10th February 1881.
ZDENKO HANS SKRAUP, Doctor of Philosophy and Lecturer of Chemistry in
the University of Vienna, Empire of Austria. "IMPROVEMENTS IN PREPARING
OXYCHINOLINES."
My Invention consists in the preparation of hydroxyle derivatives of chinoline
and its homologues, and which hereinafter shall be termed "the oxychinolines."
In order to obtain the said oxychinolines I employ a reaction analogous to that
by means of which I have effected the known synthesis of chinoline and its
homologues. The said reaction consists in the heating of glycerine and sulphuric
acid with a mixture of mononitro and monoamido compounds of benzole and its
homologues. Now I have discovered that in an analogous manner the hydroxyle-
derivatives of chinoline and its homologues may be synthetically prepared by
heating glycerine and sulphuric acid with a mixture of mononitro and monoamido
compounds of the hydroxyle derivatives of benzole and its homologues.
The said nitro and amido compounds are known to exist in several isomeric
modifications. By employing the said modifications, either in a mixed or in a
separated state, I am able to prepare isomeric oxychinolines, either mixed with or
separated from one another, as the case may be.
As an example of the manner in which my Invention may be carried into effect,
I proceed as follows:-
Ortho-nitrophenol, ortho amidophenol, glycerine, and concentrated sulphuric
acid are intimately mixed in a suitable vessel, and the mixture thus obtained is
gradually heated until an energetic reaction begins to set in. By carefully regu-
lating the temperature the reaction is allowed gently to proceed until the above
CD 471

page_text: mentioned nitro or amido compounds cease to exist in the mixture in. any
appreciable quantity. The result of the operation is then submitted to a dis-
tillation with steam in order to remove any undecomposed ortho-nitrophenol. The
residual solution is mixed with a slight excess of caustic or carbonated alkali, and
the oxychinoline thus set free may be collected on a filter and further purified by
any convenient method, or it may be separated by a distillation with steam, or it
may be extracted by means of a suitable solvent, such, for instance, as sulphuric
ether.
By employing in the above process the para and meta modifications of the said
nitro and amido phenols, corresponding isomeric modifications of oxychinoline may
be obtained.
The resulting bases not being volatile their separation may be effected by
extracting the same with sulphuric ether or any other suitable solvent, or they
may be precipitated from their acid solution by neutralizing the same with a
caustic or carbonated alkali, and the precipitate, thus obtained may be filtered and
further purified by any convenient method.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Zdenko Hans Skraup in the Great Seal Patent Office on the 13th
August 1881.
ZDENKO HANS SKRAUP, Doctor of Philosophy and Lecturer of Chemistry in
"IMPROVEMENTS IN PREPARING
the University of Vienna, Empire of Austria.
OXYCHINOLINES."
My said Invention consists in the preparation of hydroxyle-derivatives of
chinoline and its homologues, and which hereafter shall be termed "the oxy-
chinolines."
In order to obtain the said oxychinolines I employ a reaction analogous to that by
means of which I have effected the known synthesis of chinolines and its homologues.
The said reaction consists in the heating of glycerine and sulphuric acid with a
mixture of mononitro and monoamido compounds of benzole and its homologues.
Now I have discovered that in an analogous manner the hydroxyle-derivatives
of chinoline and its homologues may be synthetically prepared by heating glycerine
and sulphuric acid with a mixture of mononitro and monoamido compounds of the
hydroxyle derivatives of benzole and its homologues. The said nitro and amido
compounds are known to exist in several isomeric modifications. By employing
the said modifications, either in a mixed or in a separated state, I am able to
prepare isomeric oxychinolines, either mixed with or separated from one another,
as the case may be.
As an example of the manner in which my Invention may be carried into effect,
I proceed as follows:-
:-
About fourteen parts by weight of orthonitrophenol are intimately mixed with
about twenty one parts by weight of ortho-amido phenol, and with about sixty
parts by weight of glycerine of about 1.26 specific gravity. I then add about fifty
parts by weight of concentrated sulphuric acid of about 1.848 specific gravity, and
the mixture thus obtained is gradually heated in a suitable still or vessel provided
with a condensing arrangement which allows the condensed vapours to run back
into the said still or vessel. After a short time an energetic reaction will be
observed to set in. By carefully regulating the temperature so as not to exceed
about 130 degrees centigrade, the reaction is allowed gently to proceed for about
two hours, or until the above said nitro- or amido-compounds cease to exist in the
mixture in any appreciable quantity. The result of the operation is then submitted
to a distillation with steam in order to remove any undecomposed ortho-nitro-
phenol. The residual solution is afterwards mixed with a slight excess of a caustic
or carbonated alkali, and the oxychinoline thus set free may be collected on a
filter and further purified by any convenient method, such, for instance, as a
distillation with steam. The oxychinoline may likewise be extracted from the
alkaline mixture by means of a suitable solvent, such, for instance, as sulphuric
ether, when after evaporation of the said solvent oxychinoline will be obtained in
the solid condition. I however prefer to submit the said alkaline mixture to a
distillation with steam, when oxychinoline will be carried over with the aqueous
vapours and be found to condense in a pure and crystalline condition.
By employing in the above process the para- and meta-modifications of the said
nitro and amido phenols, corresponding isomeric modifications of oxychinolines
may be obtained.
The resulting bases not being volatile their separation cannot be effected by a
distillation with steam, as in the above described process, but other methods may
be used for the said purpose. For instance, the acid mixture resulting, as above
described, from the action of glycerine and sulphuric acid upon the nitro and

page_text: "
amido-phenols may be rendered slightly alkaline by the addition of a caustic or
carbonated alkali, and the oxychinolines thus set free may then be extracted by
means of a suitable solvent, such, for instance, as sulphuric ether, when after
evaporation of the said solvent the oxychinolines will be obtained in their solid
condition. The separation of the oxychinolines may likewise be effected by
employing the method of fractional precipitation, as is well understood by chemists.
For this purpose the above mentioned acid mixture containing the oxychinolines
is gradually mixed with solutions of a caustic or carbonated alkali until any dark-
coloured or resinous precipitates are any longer thereby produced. The mixture is
then filtered, and from the solution thus obtained the oxychinolines are precipitated
by the addition of the aforesaid alkaline solution. A further purification may be
effected by converting the oxychinolines into suitable saline compounds, say, for
instance, into their oxalates, recrystallising the said saline compounds, and liberating
the oxychinolines from the same by means of caustic or carbonated alkalies.
Having now described and particularly ascertained the nature of the said Invention,
and the manner in which the same is or may be used or carried into effect, I would
observe in conclusion that what I consider to be novel and original, and therefore
claim as the Invention secured to me by the herein before in part recited Letters
Patent is,-
The preparation of oxychinolines by the action of glycerine and sulphuric acid
upon a mixture of mononitrophenol and mono-amidophenol, substantially as herein-
before described.
In witness whereof, I, the said Zdenko Hans Skraup, have to this my
Specification set my hand and seal, this Tenth day of August, One
thousand eight hundred and eighty one.
ZDENKO HANNS SKRAUP. (L.S.)