An Improved Process for the Production of Oxygenated Pyrrazol- derivatives.
Year: 1892

page_text: Date of Application, 23rd Mar., 1892
Complete Specification Left, 20th Dec., 1892-Accepted, 18th Mar., 1893
PROVISIONAL SPECIFICATION.
An Improved Process for the Production of Oxygenated Pyrrazol-
derivatives.
We JOHANNES PFLEGER, Electrical Engineer, of 9 Blücherplatz and
WILHELM KRAUTH, Chemical Engineer, of 10 Blücherstrasse both in Frankfort-
on-Main, Germany do hereby declare the nature of this invention to be as
follows:-
This invention relates to the production of oxygen pyrrazol derivatives by the
condensation of ẞ-chlorolactic acid, or glyceric acid, or chlor-acrylic acid, and their
esters (or compound ethers) and salts on the one hand with primary or symmetrical
secondary hydrazines on the other.
It is well known that by condensing primary or symmetrical secondary hydrazines
with keton-acids or B-halogenised unsaturated or saturated fatty acids, oxygenated
pyrrazol derivatives can be obtained in the pyrrazol chain of which either two
methene or two methin groups are contained according to whether saturated or
unsaturated fatty acids have been employed.
The derivatives obtained from fatty acids and hydrazines containing two methene
groups may be easily converted by oxidation into pyrrazol derivatives, such as are
obtained directly from hydrazines and unsaturated ẞ-halogenised fatty acids, two
hydrogen atoms being abstracted in the form of water whereby two methin groups
are produced from two methene groups.
We have succeeded in effecting a condensation with saturated fatty acids whose
molecule is constantly disposed to give up water in the above manner, and this has
led to the direct production of pyrrazol derivatives containing such methin groups
and similar to those which are obtained from unsaturated fatty acids, a subsequent
oxidation being avoided.
ẞ-chlorolactic acid is an example of such a saturated fatty acid and according to
analyses made the oxygen pyrrazol derivative obtained therefrom may be
This crystallizes in diamond-glittering lamina which are readily soluble in water,
alcohol, and chloroform, but soluble with difficulty in ether. With chloride of iron,
0 it produces an intense reddish-blue reaction and forms a nitroso-derivative which is
soluble in sodium hydroxide and gives rise to a yellow color.
Glyceric acid behaves similarly and like ẞ-chlorolactic acid also contains the
CHOH group and therefore readily permits an inner hydrolitic condensation.
A confirmation of this fact was arrived at by effecting a condensation with
5 unsaturated B-chlor-acrylic acid, which latter may be viewed to a certain extent as
baving proceeded from chlorolactic acid in accordance with the following equation-
CH.CICHOHCOOH – H₂O = CHCICHCOOH + H₂O.
-

page_text: The course of the three condensations may be expressed somewhat as follows-
CONDENSATION (a) WITH B-CHLOROLACTIC ACID.
W. KRAUTH,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.
COMPLETE SPECIFICATION.
An Improved Process for the Production of Oxygenated Pyrrazol-
derivatives.
We, JOHANNES PFLEGER, Electrical Engineer, of 9, Blüchersplatz, and
WILHELM KRAUTH, Chemical Engineer, of 10, Blücherstrasse, both in Frankfort-
on-Main, Germany, Chemists, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement :-
This invention relates to the production of oxygen pyrazol derivatives which
are intended for the manufacture of pharmaceutical and industrial substances by
the condensation of ẞ-chlorolactic acid or glyceric acid or chlor-acrylic acid and
their esters (or compound ethers) and salts on the one hand with primary or
symmetrical secondary hydrazines on the other.
It is well known that by condensing primary or symmetrical secondary hydrazines
with keton-acids, or ẞ-halogenised unsaturated or saturated fatty acids (German
Patent No. 53,834) oxygenated pyrazol derivatives can be obtained in the pyrazol
chain of which either two methene or two methin groups are contained according to
whether saturated or unsaturated fatty acids have been employed.
The derivatives obtained from fatty acids and hydrazines containing two methene
groups may be easily converted by oxidation into pyrazol derivatives such as are
obtained directly from hydrazines with unsaturated ẞ-halogenised fatty acids, two
hydrogen atoms being abstracted in the form of water whereby two methin groups
are produced from two methene groups.
We have succeeded in effecting a condensation with saturated fatty acids whose
molecule is constantly disposed to give up water in the above manner, and this has
led to the direct production of pyrazol derivatives containing such methin groups

page_text: and similar to those which are obtained from unsaturated fatty acids, a subsequent
oxidation being thus rendered unnecessary.
B-chlorolactic acid is an example of such a saturated fatty acid and according to
analyses made, the oxygen pyrazol derivative which we have obtained therefrom
may be represented by the formula-
With
This substance crystallises in brilliant glittering lamine which are readily soluble
in water, alcohol, and chloroform, but soluble with difficulty in ether.
chloride of iron it produces an intense reddish-blue reaction and forms a nitroso-
derivative which is soluble in sodium hydroxide and gives rise to a yellow color.
Glyceric acid behaves similarly and like B-chlorolactic acid also contains the
CHOH group and therefore readily permits an inner hydrolytic condensation.
A confirmation of this fact was arrived at by effecting a condensation with
unsaturated B-chloracrylic acid which latter may be viewed to a certain extent
as having proceeded from chlorolactic acid in accordance with the following
equation
CHCICHCOOH + CH¸NHNH,=C¸H¸N‹
B-chlor-acrylic acid. Phenyl-hydrazine.
NHCH
\COCH
\COCH + H₂O + HCl.
Phenyl-oxypyrazol.
The condensation is performed as follows:-Molecular quantities of phenyl-
hydrazine and B-chloro-lactic-ethylether (ester) are heated for a considerable time
at 100° until a test portion becomes solid on pouring ether over it. The temperature
is then further raised to from 125° C. to 130° C. because the double linking of the
2-atom groups only takes place at a somewhat higher temperature. The reaction
will be greatly assisted by the employment of a small percentage of an indifferent
condensing medium, such as anhydrous sodium acetate. In the course of an hour
the mixture is permitted to cool down to about 100° and is then placed in ether
which dissolves a few impurities whilst leaving the pyrazolon substance in the
form of brilliant glittering lamine which after being withdrawn can be thoroughly
washed with ether.

page_text: The near relation in which B-chloro-lactic acid stands to ẞ-chlor-acrylic acid
(for the latter may be regarded as a ẞ-chloro-lactic acid minus water) caused us
to expect that the like pyrazolon derivative might be obtained with the aid of this
acid. By heating molecular mixtures of phenyl-hydrazine and B-chlor-acrylic
ether (ester) at 100° C. in the oil bath (until a test portion on having ether poured
over it becomes solid) and by then pouring into ether, a product is obtained which
proves to be identical in respect of its properties and melting point with that
produced from ẞ-chloro-lactic acid.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is―
Producing oxygenated pyrazol derivatives by condensing B-chlorolactic acid, or
glyceric acid, or B-chloro-acrylic acid and their esters (or compound ethers) and
salts on the one hand with primary or symmetrical secondary hydrazines ou the
other hand, as specified.
Dad L
ليوم
י
ԵԵԵՂՄԵԼ 1994
J. PFLEGER,
W. KRAUTH,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.