SU118502A1 - The method of obtaining vitamin B1 - Google Patents

Description

A method is proposed for producing vitamin B |, which makes it possible to simplify and cheapen its synthesis.

A distinctive feature of the process is that 2-methyl-4-amio-5-acetamidomethylpyrimidine is washed with an aqueous caustic solution. An aqueous solution of 2-methyl-4-amino-5-aminomethylpyrimidine base, after neutralizing the excess alkali with acid, is used to react with carbon disulfide, ammonia, and y-chloro-y-acetopropylacetate. The sulfuric acid formed during the oxidation of hydrochloric thio-tpaminchloride or hydrobromic thio-thiamine bromide is combined with the addition of calcium oxide to the reaction mixture.

Example. 18 g of 2-methyl-4-amino-5-acetamidomethylpyrimidine is mixed with 50 ml of a 15% aqueous solution of caustic soda, heated for 4 hours. at a temperature of 110 ° C, cool, determine the amount of free alkali, and neutralize with concentrated hydrochloric acid. 10.2 g of carbon disulphide, 26 and / l of 25% aqueous p, ammonia solution and 20 g of y-chloro-y-acetone acetyl acetate, dissolved in 80 ml of alcohol, are added for 2 hours. at 35 ° and allowed to crystallize for 8 hours. At the same time, a crystalline substance, uch-α-acetox11-propyl-y-2 (2-methyl-4-amyiopyrmmidyl-5-methyl) - dithiocarbamate, is separated, which is filtered off, washed with 20 ml of a cooled 3 () 7% aqueous solution and 20 ml of acetone.

The mother liquor and washes were concentrated and the above-mentioned substance was additionally separated, which was combined with the product of the first crystallization to obtain 18.3 g of the named dithiocarbamate.

The isolated product is mixed with 60 mg of 10% hydrochloric acid, heated to boiling and incubated for 10 minutes. When this occurs, the closure of the thiozol ring. Then the reaction mass is cooled, neutralized with concentrated sodium hydroxide solution, the resulting thiothiamine is filtered off and washed with water. The output of thiothiamine 15.2-17.5,

No. 118502-2 -

1.8 g of thio-thiamine. recrystallized from aqueous alcohol, mixed with 20 ml of water containing 4 ml of 60% nitric acid and 30 g of 15% -11th hydrogen peroxide at 30 ml of 30 ml of uiom and nitrogen acids, stirred for 20 minutes, neutralized with sodium bicarbonate and 5-10 ° C, cooled and the product crystallized at 0 °, which was separated, washed with chilled water and recrystallized from water. The yield of thiamiimonitrate is 9.6 g with a purity of 96-98%.

When preparing hydrochloride hydrochloride, thio-thiamia can be avoided. To do this, 18.3 g of dithiocarbamate are dissolved in 60 ml of 10% hydrochloric acid, heated to boiling and kept for 10 minutes, the solution is cooled to 30 ° and oxidized with hydrogen peroxide. Then, 2.5 g of calcium oxide and 0.5 g of coal are added to the reaction mass, heated to 60 °, stirred 15 MHFI., Filtered, the precipitate is washed with warm water (2x10, "1), the aqueous solution is concentrated at 50 until the product crystallizes , which is recrystallized from aqueous alcohol and: well known. The output of thiamiichloride chlorohydrate - 9.2 g

In a similar manner, hydrochloric acid hydrochloride acidioiii, p) .112.1 were used with 12.1 seconds of thiamnbromide hydrochloride.

When thio-thiamine is oxidized with hydrogen peroxide in the presence of hydrochloric or hydrobromic acid instead of nitric acid, taken in an equivalent amount, thiamine chloride hydrochloride or thiamine bromide hydrochloride is obtained, respectively. Calcium oxide is added to the reaction mass to remove the sulfuric acid formed during the oxidation of thiothiamine, and then the process is carried out as described above.

Subject invention

A method for producing vitamin B |, characterized in that, in order to simplify the 2-methyl-4-amio-5-acetamidomethylpyrimidium process, an aqueous solution of caustic alkali is washed with an aqueous solution of 2-methyl-4-amino-5-aminomethylpyrimidine base after neutralizing the excess alkali acid is used to react with carbon disulfide, ammonia and γ-chloro-acetopropylacetate, which is formed by the oxidation of hydrochloric thiothiamine chloride or hydrobromic thiothiamine bromide, sulfuric acid is added by adding calcium oxide to the reaction mixture.