DE68719C - Process for the preparation of p-ethoxyphenylhydrazine and p-ethoxyhydracetin - Google Patents

Description

IMPERIAL

PATENT OFFICE

_{The hydracetin (acetphenylhydrazine), C 6} H _s · N ₂ H ₂ · C ₂ H ₃ O, which was brought onto the market by the inventor some time ago, shows not only strong typical properties but also toxic side effects that stand in the way of its technical exploitation . Since it is now possible to get from the antifebrin (acetanilide), which is also fraught with harmful side effects, to a harmless antipyretic, phenacetin (p-ethoxyacetanilide) by introducing an ethoxyl group in the para position to the acetamido group, an attempt was made to also use a p-ethoxyl compound of hydracetine to win. To this new, previously unknown body, the p-ethoxyacetphenylhydrazine,

_{Γ H} / ^ ₂ H ₂ -C, H ₃ O (ή

if you get p-amidophenetol,

' , NH ₂ (I)

converted into the corresponding hydrazine salt and this into the acetone compound.

The conversion of the p-amidophenetol into the p-ethoxyphenylhydrazine succeeds Action of reducing agents on the diazo compound of amidophenetol, but deliver the previously known regulations for this implementation, z. B. those for the presentation of phenylhydrazine, for p-amidophenetol. only unsatisfactory yields. It has been found most expedient to use reduction the diazo compound after conversion into the diazosulfonic acid salt by the method made by fishermen with zinc dust in acetic acid solution. Since, however, the resulting hydrazinesulfonic acid salt which differs from the analogous compounds known to date Property showed, extremely easily decomposed on treatment with aqueous hydrochloric acid a completely new method for splitting off the sulfonic acid group had to be found will. The same consists in the treatment of the ρ - ethoxyhydrazinesulfonic acid salt with alcoholic hydrochloric acid. The hydrazinesulfonic acid salt and, in order to do so, had to be obtained to be able to isolate the diazosulfonic acid salt in dry form, what because of the relatively high solubility of both compounds according to the known rules likewise cannot be achieved in good yield. However, it was poorly soluble of both compounds in concentrated saline solutions found a means for the same to be able to fall almost completely out of their solutions. The representation happens as follows: p-amidophenetol,

₂ (ή

C ₂ H ₆ (4) '

is in the form of one of its salts in aqueous concentrated solution - in a known manner in the diazo compound transferred, the solution obtained in a concentrate kept alkaline Entered a solution of sodium sulfite and the resulting crystal pulp with table salt or Saline solution until the p-ethoxydiazobenzene sulfonic acid sodium has precipitated completely,

_r π / N: NSO ₃ Na (I)

^C «^ XOC ₂ / Z ₅ (4)

offset, which is deposited in the form of yellow, shiny leaves. Become the same filtered off, washed with saline, and pressed off. For conversion into hydrazinesulfonic acid Salt,

_r "

^{6 4}

H ₂ S0 ₃ Na (i)

the obtained mass is dissolved in as little water as possible, filtered, acidified with acetic acid, mixed with zinc dust until it was discolored, filtered, and the colorless filtrate from which on cooling the sodium p-ethoxyhydrazine sulfonic acid in the form of colorless, crystalline Partly separates the precipitate, with common salt or common salt solution for complete precipitation of the hydrazine salt added. The same is then filtered off and pressed dry. To the spin-off the sulfonic acid group is then added to the salt with alcohol with the addition of hydrochloric acid digested and hot filtered when the reaction is complete. This separates from the filtrate Chlorohydrate of p-ethoxyphenylhydrazine,

₃ ()

₂ H ₅ (4) '
as a white crys- tallial mass which is obtained by filtering off, washing out with alcohol, and pressing, and which can be recrystallized from dilute alcohol for purification. ■

The acetone compound of p-ethoxyphenylhydrazine is obtained in a known manner from the chlorohydrate,

KHCHO ()

₂₃ () ₂ H ₅ (4)

by either precipitating the free hydrazine by means of alkali, sodium acetate, etc. and this is digested with glacial acetic acid, or by adding the hydrochloric acid salt directly Treated the required amount of sodium acetate with glacial acetic acid.

The acetone compound is obtained in pure form from the residue obtained after the excess acetic acid has been distilled off and solidified on cooling by recrystallization from water or alcohol. It forms of alcohol crystallized colorless, melting at about 140 ⁰ shiny prisms.

Sodium ethoxyhydrazinesulfonic acid, ethoxyphehylhydrazine with hydrochloric acid, and acetethoxyphenylhydrazine have the property of reducing Fehling's solution even in the cold and with great dilution.
. It goes without saying that in the above process, instead of sodium sulfite, other sulphurous acid salts can also be used; likewise, to precipitate the diazosulphonic acid and hydrazinesulphonic acid salt, other inert salts can be used instead of common salt and acetic anhydride or other acetylating agents instead of glacial acetic acid.

Example.

I. 10 kg of p-amidophenetol are stirred in 75 kg of water and 14 kg of hydrochloric acid 1.19 are added. 5.7 kg of nitrite, dissolved in 40 kg of water, are gradually added to the crystalline slurry, while the mixture is cooled, the filtrate is filtered after standing for a while, and the filtrate is dissolved in a solution of ig kg of crystallized sodium sulfite in 150 kg of water ( ^l / ' _A as ice ) and 2 kg of sodium hydroxide solution of 39 ⁰ B. run in and add 40 kg of table salt. After the latter has dissolved, it is filtered off and pressed off. The mass obtained is sodium p-ethoxydiazobenzene sulfonic acid.

II. 10 kg of dry diazosulfosalt, dissolved in 40 kg of hot water, are mixed with 0.4 kg of glacial acetic acid and 0.5 kg of zinc dust is added until it is discolored, filtered and dissolved in 60 l of saturated sodium chloride solution entered. After strong cooling, it is suctioned off and pressed. The received Mass is sodium p-ethoxyhydrazine sulfonic acid.

IH. ι ο kg dry hydrazine sulfosalt will be with 60 kg of fuel 95 pCt. digested, added 10 kg of hydrochloric acid 1.19 after a short time Boil filtered, the filtrate strongly cooled and allowed to crystallize. The crystal pulp is squeezed, washed with fuel and dried. The mass obtained is the hydrochloride of p-ethoxyphenylhydrazine.

IV. A) 10 kg of the above hydrochloride, dissolved in as little water as possible, are concentrated with Solution of 7.3 kg of crystallized sodium acetate precipitated, the precipitate quickly sucked off and. pressed dry and then Digested with 5 kg of glacial acetic acid for 24 hours.

. b). 10 kg of the above hydrochloric acid hydrazine, 6 kg of anhydrous sodium acetate and 15 kg of glacial acetic acid are digested for 24 hours.

In the process according to a) or b), the excess glacial acetic acid is then distilled off, the residue cooled and, after solidification, recrystallized from water or alcohol. Excess Sodium acetate and ethoxyphenyl hydrazine remain in solution, while acetethoxyphenyl hydrazine crystallized out.

Claims (2)

Patent Claims: 1. Process for the preparation of p-ethoxyphenylhydrazine respectively its salts, consisting in the fact that one p-ethoxyphenylhydrazinesulfonic acid Salts fall from their solutions due to mineral salts and then with alcoholic Treated with hydrochloric acid. 2. Process for the preparation of p-ethoxyhydracetin, consisting in the fact that one is protected according to what is protected by claim 1 The ρ-ethoxyphenylhydrazine shown in the process is acetylated.