Improvements in the Manufacture or Production of Basic Compounds Derived from Pyrazine.
Year: 1893

page_text: t
Date of Application, 2nd May, 1893
**Complete Specification Left, 2nd Feb., 1894-Accepted, 10th Mar., 1894
PROVISIONAL SPECIFICATION.
I...
[Communicated from abroad by THE FARBENFABRIKEN vormals FRIEDRICH
BAYER & Co., 'of Elberfeld, in the Empire of Germany.]
Improvements in the Manufacture or Production of Basic Compounds
Derived from Pyrazine.
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:-
Etard (see Comptes rendus, volume 92 of the year 1881, pages 460 and 795)
obtained, by heating glycerine with ammonium chloride, a basic compound which
he considered as a hydroxypicoline of the formula C.H.NO. Afterwards he
ascribed to the said product the formula C,HN, and termed the same
"glycoline." This author (as he himself says) was not able to account for the
constitution or composition of the above compound.
As described in the " Berichte der Deutschen Chemischen Gesellschaft,"
volume 19, page 2456, Storch obtained pyrdine bases in distilling glycerine with
ammonium sulphate or ammonium phosphate.
Stöhr succeeded in proving that the distillates resulting in distilling glycerine
with ammonium salts also contain homologues of the pyrazine, which could be
easily separated from pyridine bases simultaneously formed, by means of their
mercuric, salts (see the notes of Stöhr in the "Journal für practische Chemie,"
volume 43, page 156, and in the "Berichte der Deutschen Chemischen Gesellschaft,"
volume 24, page 4105, and of Dennstedt in the "Berichte der Deutschen Chemischen
Gesellschaft," volume 25, page 259.
Stöhr has examined more in detail amongst these pyrazine bases, that product
which he termed as "dimethyldiazine," and which has the formula:
CH₂(CH3)2N2, or CH.N₂.
It is to be noted, that by means of the methods hitherto known, riz., by
distilling glycerine with ammonium salts, either pyridine bases alone, or mixtures
of pyridine bases and pyrazine derivatives have been obtained.
for
My foreign correspondents have now found, that these pyrazine bases alone are
formed by heating glycerine with ammonium chloride or ammonium bromide, with
the addition of products capable of giving off ammonia with ease, such as,
instance, ammonium carbonate, carbamide of ammonia, or other inorganic or
organic ammonium salts. According to the researches of my foreign corre
spondents, the distillates resulting in this manner contain no derivatives of pyridine,
but only the homologues of pyrazine mixed with water, ammonia, and substances
possessing an aldehyde-like smell, the 2:5-dimethylpyrazine being formed as
chief product, whilst the dimethylethylpyrazine is produced to a slight extent
only.
In order to illustrate this process, the following example is given, the parts
being by weight :-
300 parts of glycerine are distilled with from 100 to 120 parts of ammonium
chloride, and from 30 to 50 parts of ammonium carbonate. The substances
having no basic properties are then removed from the distillate, by acidulating
the latter, and subsequently distilling with steam. From the remaining liquid,
the pyrazine bases are separated by means of alkali, and then isolated from the
water liquid.

page_text: The mixture of pyrazine bases thus obtained is then distilled, in order to
separate the homologous pyrazines, riz., the dimethylpyrazine, and dimethylethyl-
pyrazine.
The dimethylpyrazine is identical with the dimethyldiazine described by Stöhr as
above mentioned, boils at 155 degrees centigrade (with the so-called correction), and
possesses the following composition :-

page_text: My foreign correspondents have described in the above example, a distinct
method for obtaining pyrazine bases from glycerine, and of course they do not limit
themselves to the directions given therein, nor to the quantities of the agents employed
therein. The manner of working described in the above example can be varied; for
instance, in place of ammonium carbonate, other agents giving off easily ammonia, such
'as carbamide of ammonia or the like, can be used.
The nature of this invention is not altered by such or similar modifications, as the
present invention generally relates to the production of a mixture of pyrazine bases
containing no pyradine bases from glycerine.
Dated this and dow of New 1002
NEWTON & SON,
Agents for the Applicant.
Improvements in the Manufacture or Production of Basic Compounds
Derived from Pyrazine.
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
particularly described and ascertained in and by the following statement :-
Etard (see Comptes rendus, volume 92, of the year 1881, pages 460 and 795), by
heating glycerol (glycerine) with ammonium chloride, obtained a basic compound
which he considered was a hydroxypicoline of the formula: C,H.NO. He after-
wards ascribed to the said product the formula C.H₁N,, and termed it "glycoline."
This author (as he himself says) was not able to account for the constitution or
composition of the said compound.
Storch subsequently obtained pyridine bases by distilling glycerol with ammonium
sulphate or ammonium phosphate, as described in the "Berichte der Deutschen
Chemischen Gesellschaft," volume 19, page 2456.
Stöhr succeeded in proving that the products obtained on distilling glycerol with
ammonium salts, also contain homologues of pyrazine, which could be easily
separated from the pyridine bases simultaneously formed, by means of their mercuric
salts (see Stöhr's notes in the "Journal für practische Chemie," volume 43,
page 156, and in the "Berichte der Deutschen Chemischen Gesellschaft,"
volume 24, page 4105, and of Dennstedt in the "Berichte der Deutschen Chemischen
Gesellschaft," volume 25, page 259).
Of these pyrazine bases, Stöhr has examined more in detail the product which he
termed "dimethyldiazine," and which has the formula:-
·
CH,(CH₁),N, DI CHEN,
זו זT
UI
1 11
1
L
It is to be noted, that by means of the method's hitherto know, is, by distilling
glycerol with ammonium salts, either pyridine bases alone, or mixtures of pyridine
bases and pyrazine derivatives, have been obtained.
My foreign correspondents have now found, that these pyrazine bases are alone
formed by heating glycerol, either with ammonium chloride or ammonium bromide,
and substances capable of readily giving off ammonia, such as, for instance,
ammonium carbonate, animonium carbamate, ammonium ortho-phosphate, ammonium
pyrophosphate, ammonium sodium orthophosphate, or other inorganic or organic
ammonium salts. According to the researches of my foreign correspondents, the
distillates obtained in this manner, do not contain derivatives of pyridine, but only
homologues of pyrazine mixed with water, ammonia, and substances possessing an
aldehyde-like smell, 2:5 dimethylpyrazine being formed as chief product, and
only a small proportion of dimethylethylpyrazine.

page_text: In order to illustrate this process, the following example is given, the parts
being by weight :-
300 parts of glycerol are mixed with from 100 to 120 parts of ammonium
chloride, and from 30 to 50 parts of ammonium carbonate, and the resulting mixture
is distilled. The non-basic substances are then removed from the distillate, by
acidulating the latter, and subsequently distilling with steam. The remaining
liquid is rendered alkaline and is then distilled. When the bases have entirely
distilled over, alkali in solid state is added to the distillate. The bases, which are
insoluble in the resulting concentrated alkaline solution, are in this way separated
as an oily mass which can easily be isolated.
•
The mixture of pyrazine bases thus obtained is then distilled, in order to separate
the homologous pyrazines, viz.: dimethylpyrazine and dimethylethylpyrazine.
The process proceeds in an analogous manner, if a mixture of 500 parts
of glycerol, 125 parts of ammonium chloride, and 42 parts of ammonium
phosphate, is distilled, and the resulting distillate is treated in the manner above
set forth.
The dimethylpyrazine- so formed is identical with the dimethyldiazine described
by Stöhr, as above mentioned. It boils at 155 degrees C. (corrected), and is
termed 2.5 dimethylpyrazine (see Journal für praktische Chemie, Neue Folge,
volume 47, of the year 1893, page 454), being represented by the following
Ր
The formula above given to dimethylpyrazine is further established by the fact 3
that the said product is identical with the so-called ketine prepared from isonitroso
acetone, as described in the "Berichte der Deutschen Chemischen Gesellschaft,"
volume 15, page 1059.
The second pyrazine obtained by means of the above defined process, has the
formula C.H,N,, and is a dimethylethylpyrazine. It distils undecomposed, and is 3
a highly refractive liquid, boiling at from 178 to 179 degrees centigrade (corr.).
It can be mixed with water in any proportion. When treated with oxidising agents,
it yields a dimethylpyrazinemonocarboxylic acid, which can be converted into the

page_text: (2)
CH 3
C:
C₂ H 5
My foreign correspondents have described in the above example, a distinct method
of obtaining pyrazine bases free from pyridine derivatives from glycerol; of course,
they do not limit themselves to the directions given therein, nor to the quantities of
the agents employed therein. The manner of working described in the above
example can be varied; for instance, in place of ammonium carbonate, other agents
which easily give off ammonia, such as carbonate of ammonia, or ammonium salts of
orthophosphoric or. pyrophosphoric acid, ammonium sodium orthophosphate, or the
like, can be used.
The nature of this invention is not altered by such or similar modifications, as the
present invention relates generally to a process for producing pyrazine bases (free
from pyridine bases) from glycerol, which process consists in distilling mixtures
prepared from glycerol, ammonium chloride, or ammonium bromide, and such
ammonium compounds as easily give off ammonia.
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:
The process for producing 2:5 dimethylpyrazine and 2:5-dimethyl-3-ethyl-
pyrazine, by distilling mixtures of glycerol, and either ammonium chloride or
ammonium bromide, together with ammonium carbonate or ammonium phosphate,
or other ammonium compounds capable of giving off ammonia with ease.
Dated this 1st day of February 1894.
NEWTON & SON,
Agents for the Applicant.