Year: 1890

page_text: Date of Application, 26th June, 1890
Complete Specification Left, 25th Mar., 1891-Accepted, 26th June, 1891

page_text: It is shown that the oxidizing process consists in the withdrawal of two atoms of
hydrogen from the fatty acid remainder CH,-CH2. For carrying out this
operation the phenylpyrazin is treated in cold chloroform or benzol-solution with
an oxidizing agent having slight action, such as oxide of mercury; 20 grammes
phenylpyrazin are dissolved in 500 grammes chloroform and are shaken together
with 32 to 35 grammes of dry oxide of mercury.
Dehydrophenylpyrazine is readily soluble in benzol and chloroform, and is
obtained from the solutions in fine crystallized flat needles; it melts at 154° Cent.
III. DEHYDROMETHYLPHENYLPYRAZINE.
By heating the dehydrophenylpyrazine with methyl iodide and wood spirit to
100° C. "dehydromethylphenylpyrazine" will be obtained. It crystallises from
chloroform in large crystals having a melting point of 120° C. It is readily
soluble in water, and possesses strongly basic properties.
Dehydromethylphenylpyrazine possesses valuable antipyretic properties.
Dated this 26th day of June 1890.
ABEL & IMRAY,
Agents for the Applicant.
I. Phenylpyrazine (PhenylhYDROPYRAZOLON).
a. If free B-halogen substituted propionic acid or its salts be used, equivalent
quantities thereof (3-bromic- B-chloric- B-iodic-propionic acid) and phenylhydra-
zine, in solution (in water, alcohol, or benzol) are heated on the steam bath until
no more free phenylhydrazine exists. By shaking with water, the phenylpyrazine
(phenylhydropyrazolon) is separated.
b. If the esters are employed, equivalent quantities of bromic propionic acid ester
(or B-chloric or ẞ-iodic propionic acid esters) and phenylhydrazine in weak alkaline
solution are heated on the steam bath, until the odour of the ester has vanished.
On pouring into cold water the phenylpyrazine (phenylhydropyrazolon) separates
as oil.
The phenylpyrazine (phenylhydropyrazolon) corresponds to the composition
CH NO and has the atmustunal fanmul

page_text: The phenylpyrazine (phenylhydropyrazolon) is soluble with difficulty in cold
water and benzole, it is somewhat more readily soluble in hot benzole, and easily
soluble in alcohol and chloroform; it separates from it solutions in the form of
laminæ, fine flat needles, or plates, which melt at 121° C.
II. DEHYDROPHENYLPYRAZINE.
As briefly stated above the further treatment of the phenylpyrazine (phenyl-
hydropyrazolon) is based on its oxidation.
The result thereof is "dehydrophenylpyrazine." Its composition corresponds
to the formula CH₂N,O and it has the structural formula:
III. DEHYDROMETHYLPHENYLPYRAZINE.
By heating the dehydrophenylpyrazine with methyl iodide and wood spirit to
100° C. "dehydromethylphenylpyrazine" will be obtained. It crystallises from
chloroform in large crystals having a melting point of 120° C. It is readily
soluble in water, and possesses strongly basic properties.
Dehydromethylphenylpyrazine possesses valuable antipyretic properties.
Having now particularly described and, ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
The manufacture of dehydromethylphenylpyrazine, produced by first converting
phenypyrazine (phenylhydropyrazolon), obtained by the condensation of B-halogen
propionic acid or its esters and phenylhydrazin, into dehydrophenylpyrazine, and
then converting the latter into dehydromethylphenylpyrazine by methylisation,
substantially as described.
1
ABEL & IMRAY,
Agents for the Applicant.