SU181556A1 - METHOD OF OBTAINING AMINO ACIDS - Google Patents

Description

A known method for producing a-amino acids is that hydantoin is reacted with aryl aldehyde. The resulting 5-aralkylidene derivative is reduced to the 5-aralkyl derivative and then hydrolyzed to the amino acid.

The proposed method for the production of a-amino acids is that the hydantoin is reacted with a metal alkyl carbonate (Ca, Mg, Zn) at a temperature of 60 ° C. The resulting metal complex of the corresponding 5-carboxyhydantoin is alkylated by various alkylating agents (haloalkyls, ketones, Mannich bases, etc.) at a temperature of 110 ° C, followed by hydrolysis of the resulting 5-substituted hydantoin at a temperature of 150 ° C.

Example 1. Hydantoin is dissolved in magnesium methyl carbonate in a proportion of 0.05 g of hydantoin per 50 ml of a 2 fA solution of magnesium methyl carbonate. The complex is formed by heating the reaction mixture in an atmosphere of nitrogen and another inert gas at 60 ° C for 1.5 hours, after which 0.055 mol of alkylating agent is added. In most cases, all the alkylating agent can be added immediately. However, when methyl iodide, benzyl chloride and a-phenethyl bromide are consumed, the reaction proceeds as much

vigorously that the halogen is added dropwise. In the case of benzoyl chloride, the reagent must be added gradually to the reaction mixture, cooling it to 5 ° C.

The reaction mixture is heated to 110 ° C for 5 hours or refluxed if the alkylating agent has a low boiling point. In the latter case, the temperature is gradually increased to 110 ° C to the extent that

how the alkylating agent is consumed. After cooling, the reaction mixture is poured with vigorous stirring into a mixture consisting of 25 ml of concentrated hydrochloric acid and 100 g of ice. The product is separated and crystallized in a short time. A higher yield is obtained when the hydrolysable mixture is left at 5 ° C for the whole of 1/3 to complete the crystallization. The crystalline hydantoin is then removed from the reaction mixture by filtration.

In tab. Table 1 shows the hydantoins used, alkylating agents, hydantoin products, their melting point and yield. In all cases when the resulting hydantoin is unknown from the literature, it is determined by spectroscopy, nuclear magnetic resonance, or chemical analysis, depending on

Benzyl chloride (a)

Benzyl chloride methyl a-phenethyl

P10 DYNMY Methyl Benzyl Chloride 1-Bromo O-Z-methi Forehead Tai Methyl Isobutyl Methyl | 3-Phayethyl Iodide Methyl (a) Methyl Iodide

-Feiil Methyl isoiropyl 1,3-Dibromopropy 2,6-Dimethpl-5-chloromethylpizil Bepzaldehyde Gentpldehyde Ethyl chloroformate (d)

Chloromethyl benzyl sulfide

Benzyl chloride 3 1,4-Dibromobutane Beisoyl chloride Benzoic anhydride

 a) Ispolzuetts doubled: the amount of alklating agent;

b) due to the asymmetry of the carbon atom, two distereisomers were found. After recrystallization of the mixture, one of the two isomers, with a low melting point, is selected and dissolved in benzene. The high melting point isomer is a solution of 1mol in the rapole;

c) both of these compounds are a mixture of two distereisomers and, therefore, do not have an exact point of fusion. Isomers are not easily separated by selective dissolution. In order to give the hydantoin a pronounced cleavage point, it is dehydrated by heating it with an aqueous solution of sulfuric acid to obtain 3-phenyl-b-benzylidene hydantoin with m.p. 25th-257 ° C and 3-phenyl-5-heptylideneidantium with m. Pl. 125-128 ° C, which are not mixtures;

(d) This acyl halide is iastol, reactive, which, although only equimolar amounts are used, results in the alkylation of two 1- and 3-polio.

PRI AND. M e p 2. The hydantoins listed in table. 2, are obtained in an I-liter flask with necks, equipped with a gas inlet tube, a thermometer, a magnetic stirrer and a vent tube, by dissolving 44 h3-feiylgndantoin in 2.1 M of magnesium methyl carbonate. The solution is heated to 80 ° C and held for 2 hours under a slow stream of nitrogen to obtain a magnesium complex of 3-phenyl-5-carboxyhydantoin. At this time, the alkylating agent is added to the solution, the temperature is raised to 100 ° C and maintained at this temperature for 5 hours. Then the solution is cooled to room temperature and poured onto a mixture of 600 g of ice and 150 ml of concentrated hydrochloric acid. After allowing to stand in the refrigerator for 24 hours, the precipitated product is filtered off. Extraction of the filtrate with chloroform indicates that the whole product has turned into a precipitate, since the evaporation of chloroform stops the further yield of the product.

3,5-Dibeisil (g. E. 3,5-dnBen145-146

zilgidaiton) 3,5-Dibeisil

3-Be113yl-5-a-fayet11l (b)

Z-Bsnzil-5-methyl

3-Phenyl-5-beisyl

Z-Feiil-5-isoamil

3-Phenyl-5-isobutyl

3-Phenyl-5-p-phenethyl

3-Phenyl-1,5-dimeti l

3-Phenyl-1,5-dnmetil

Z-Feiil-5-isoproyl

1,5-Trimethylio-3-phenyl

3-Fae 11L-5- (3,5-dimethyl-4-methoxybenzyl)

3-Feiil-5-cc-hydroxybeisyl 3-Phenyl-5-a-hydroxyhethyl 1,5-di- (carboethoxy) -3-phenyl

(a) 3-Phenyl-5-benzyl11-methyl

3-Decyl-5-benzyl 1,5-Tetramethylamine-3-phenyl 3-Phenyl-5-beisoyl 3-Phenyl-5-beisoyl

table 2

Z-Feiil-5-isonronil; 40 123-125 3-Feiil-5-isob til 66 I 126-127

l

98 i 170-172

Z-Phenyl-5-beisyl Z-Phenyl-5-skatil | 55 173-175

117-119

3-Feiil-1,5-trimeti-48

lei

Z-Feiil-5- (p-phthal-53: 117-119

midobutyl) i

3-Phenyl 5 - ((5-carb-561 168-169

:

sietil)

the corresponding α-amino acid. This example shows the general method of hydrolysis. Hydantoip and barium hydroxide octahydrate are placed in a stainless steel lining of a pressure autoclave under agitation conditions, and sufficient air is added.