JPS60224661A - Production of alpha-amino acid - Google Patents

Abstract

PURPOSE:To produce the titled compound useful as pharmaceuticals, feeds, etc., in high yield, in a short time, by hydrolyzing a hydantoin compound in the presence of ammonia or ammonium carbonate. CONSTITUTION:The objective compound can be produced by heating hydantoin or 5-substituted hydantoin derivative of formula (R1 and R2 are H or 1-4C alkyl) in the presence of ammonia or a carbonate of ammonia capable of releasing ammonia by heating. The hydrolysis of the hydantion compound can be accelerated by this process. The heating temperature is preferably 100-200 deg.C. EFFECT:Since the objective compound can be separated extremely easily, the process is very economical for the industrial operation.

Description

[Detailed description of the invention] The present invention relates to a method for producing α-amino acids.

More specifically, the present invention relates to a method for producing a corresponding α-amino acid by hydrolyzing a hydantoin or a 5-substituted hydantoin derivative.

The α-amino acids obtained by the method of the present invention are directly useful as foods, feeds, and medicines, and are also useful as intermediates for agricultural chemicals, medicines, and polymers.

Conventionally, in order to hydrolyze hydantoins to produce the corresponding α-amino acids, strong alkalis such as sodium hydroxide or barium hydroxide, or strong acids such as sulfuric acid or hydrochloric acid are required; An amount equivalent to or more than hydantoin is required.

Moreover, when recovering the α-amino acids produced after hydrolysis, neutralization with acid or alkali is necessary.

For example, U.S. Pat. No. 2,525,745, U.S. Pat.
Specification No. 27366, Specification No. 2557920, and Journal Fist of American Chemical Society 672218 (1945), Journal No. 450 (1946)
), Domu 450 (1946), Domu 701450 (
1948) not only requires the use of large amounts of acids and alkalis, but also requires separation of the salt produced for neutralization and the target amino acid;
It is complicated and uneconomical to implement industrially.

Furthermore, a method of significantly reducing the amount of alkali metal or alkaline earth metal hydroxide used by hydrolyzing the alkali metal or alkaline earth metal hydroxide in combination with ammonia (% Kosho 58 -2227), but since this method also uses essential KFi alkali metals or alkaline earth metals, it is necessary to separate the salt produced by neutralization and the target amino acid, and it is difficult to implement it industrially. Not economical.

Therefore, the present inventors conducted extensive studies on the hydrolysis of hydantoins without using strong acids or strong bases, and as a result found that the hydrolysis of hydantoins was accelerated by the presence of ammonia, and completed the present invention.

That is, the present invention provides a hydrogen atom having the general formula (1) (wherein R] and R2 are a hydrogen atom or a carbon atom number of 1 in the presence of ammonia or a carbonate of ammonia.
This is a method for producing an α-amino acid, which is characterized by hydrolyzing hydantoins represented by the following formulas (representing a linear or branched alkyl group).

In the method of the present invention, by heating hydantoins with ammonia or an ammonia carbonate that dissociates ammonia by heating, ammonia surprisingly accelerates the hydrolysis of hydantoins at the initial stage of the reaction, and the hydantoins are hydrated. It is thought that ammonia generated by decomposition subsequently promotes hydrolysis.

Therefore, according to the method of the present invention, α-amino acids can be obtained in a short time and in high yield, and the reactant can be ammonia or ammonia carbonate, and the substances produced together with the target product can be reacted with each other, such as carbon dioxide and ammonia. After completion of hydrolysis, it is very easy to remove by heating under reduced pressure. Therefore, after the completion of hydrolysis, simply heating under reduced pressure is sufficient to remove α-amino acids as by-products and additives. It can be easily distinguished.

The hydantoins used in the method of the present invention have the general formula (
1), such as hydantoin,
5-methylhydantoin, 5,5-dimethylhydantoin, 5-ethylhydantoin, 5゜5-diethylhydantoin, 5,5-methylethylhydantoin, 5-n-
Propylhydantoin, 5-isopropylhydantoin, 5.5-diisopropylhydantoin, 5-n-butylhydantoin, 5-inobutylhydantoin, 5-
5ec-butylhydantoin, 5.5-di-5eC-butylhydantoin, and the like.

In addition, ammonia can be obtained by blowing gaseous ammonia into the hydrolysis solution, or ammonia water, for example, commercially available 29
Thiammonia water may also be used.

Carbonates of ammonia include ammonium bicarbonate, ammonium carbonate, and ammonium salts of carbamic acid. All of these generate ammonia when heated, promoting hydrolysis of hydantoins.

The amount of ammonia or ammonia carbonate used in the method of the present invention is preferably 01 to 6 equivalents relative to the hydantoin. If the amount is less than 0.1 equivalent, the effect will be small, and if it is added in excess of 6 equivalents, no further effect will be obtained.

The amount of water is preferably 1 to 20 times the weight of the hydantoins.

If the amount is less than 1 times the weight, it will take a long time for hydrolysis, which is undesirable, and if it is used in an amount exceeding 20 times the weight, no further effect will be obtained.

In the method of the present invention, first, hydantoins, ammonia or ammonia carbonate, and water are sealed and heated for a certain period of time. At this time, the pressure inside the reactor increases due to ammonia and carbon dioxide generated as the hydantoins are hydrolyzed. If necessary, the pressure in the reactor may be reduced to the water vapor pressure at the temperature during hydrolysis. This is preferable in view of the material of the reactor.

The heating temperature is 100 to 200°C, and if it is less than 100°C, the rate of hydrolysis becomes slow and is not practical. On the other hand, 20
If the temperature exceeds 0°C, the resulting α-amino acid will be decomposed, which is not preferable.

The hydrolysis time varies depending on the reaction temperature, but is 1-
20 hours is preferred. If the reaction time is short, the desired product cannot be obtained in a sufficient yield, and a reaction time within the above range is required to achieve a sufficient yield.

After the hydrolysis is completed, the decomposition liquid may be concentrated to dryness, and the residue may be recrystallized from water.

As described above, the present invention provides an extremely economical method for industrially implementing the method for producing α-amino acids from hydantoins, since it is extremely easy to separate the target product.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 600m1 with pressure gauge, exhaust port, and thermometer insertion tube
Hydantoin was placed in a magnetic stirring autoclave for 10 to 2 hours.
After putting 122 parts of 9% ammonia water and 100 parts of water in the container and sealing it, the temperature was raised to 170°C. At this time, the pressure gauge is 10 to 97-
showed that. Thereafter, whenever the internal pressure rose, the exhaust port was opened to maintain the pressure at 10 to 9/-. and 5
Stirring was continued at 170°C for an hour.

The autoclave was then rapidly cooled to room temperature. After purging the residual pressure, the autoclave was opened and the contents were thoroughly washed with water and taken out. The obtained decomposition liquid was evaporated to dryness using a rotary evaporator, and the obtained solid was recrystallized from water to obtain crystals of 642. Yield 85 cm, 232-26
6°C (decomposition) elemental analysis CHN as C2H,N□02 Theoretical value (%) s2. oo 6.71 1866 Actual value (%) 32,15 6.9o 18.39 Comparative example 1 500m1 with pressure gauge, exhaust port, and thermometer insertion tube
Hydantoin 1 (l) and water 1002 were charged into a magnetically stirred autoclave, the autoclave was sealed, and the temperature was raised to 170°C. At this time, the pressure gauge showed 8.0 kg/al.

After 30 minutes, it became 10 Kp/cJ. After that, every time the internal pressure rises, open the exhaust port to 10Kp/ctd.
I tried to maintain it. Stirring was then continued at 170° C. for a total of 5 hours. The autoclave was then rapidly cooled to room temperature.

After purging the residual pressure, the autoclave was opened and the contents were taken out while thoroughly washing with water. The obtained decomposition liquid was evaporated to dryness using a rotary evaporator, and the obtained solid was recrystallized from water to obtain crystals of 5.12. Yield 68 CHN elemental analysis CHN as C2H3N engineering 02 Theoretical value (%) 32,00 6.71 18.66 Actual value ←) 31.95 6.49 18.54 Example 2 In the same autoclave as Example 1 51.2 Y of 5,5-dimethylhydantoin, 38 A2 of ammonium carbonate, and 512 g of water were put in the flask, and the flask was sealed, and the temperature was raised to 160°C.

At this time, the pressure gauge showed 9/cn at 5.0. After that, every time the internal pressure rises, open the exhaust port to 5Kg/d.
I tried to maintain it. Stirring was then continued at 130° C. for 10 hours. Thereafter, it was treated in the same manner as in Example 1, and recrystallized from water to yield 55Bf! crystals were obtained.

Yield 82% Elemental analysis CHN Theoretical value (a) 46.59 8°79 13.58 Actual value (a) 46.71 89113.39 Comparative example 2 5,5-dimethylhydantoin 51 was placed in the same autoclave as in Example 1. .2 F and water 512? After filling the container and sealing it, the temperature was raised to 130°C. At this time, the pressure gauge is 4.0~/-
However, 60 minutes later, it showed 5.0 I'4/crA.

After that, every time the internal pressure rises, open the exhaust port and
I tried to maintain 9/-. Stirring was then continued at 130° C. for a total of 10 hours. Thereafter, it was treated in the same manner as in Example 1 and recrystallized from water to obtain crystals of 26B2. Yield 6
5% Elemental analysis CHN as C4H, N102

Claims (1)

[Claims] 1) General formula (+) 2 1 (wherein R1 and R2 are hydrogen atoms or have 1 carbon atom
α characterized by hydrolyzing hydantoins represented by ~4 straight-chain or branched alkyl groups) in the presence of ammonia or ammonia carbonate.
-A method for producing amino acids.