# US 4,400,533 A · Method of preparing d,l-phenylalanine

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- Number: US 4,400,533 A
- Document ID: US4400533A
- Status: Granted
- Kind: A
- Application number: 06/346,824
- Filed: 1982-02-08
- Granted: 1983-08-23
- Earliest claimed: 1979-08-01
- Assignees: Dynamit Nobel Aktiengesellschaft
- Inventors: Helmut aus der Funten; Klaus Schrage
- Web page: https://patentgrep.com/patent/US4400533A

## CPC

- C07C 227/08: by reaction of ammonia or amines with acids containing functional groups
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

A process for preparing an alkali salt of d,l-phenylalanine and the free acid thereof is disclosed. According to the invention an alkali salt of phenylpyruvic acid is reacted at elevated pressure with hydrogen and ammonia in the presence of a noble metal catalyst of Group VIII. If the acid is desired it is obtained by acidification of the corresponding salt.

## Claims

### Claim 1

A method for preparing an alkali salt of d,l-phenylanine, which comprises containing an alkali salt of phenylpyruvic acid with hydrogen and ammonia at elevated pressure in the presence of a noble metal catalyst of Group VIII of the Periodic Table.

### Claim 2 (depends on 1)

A process according to claim 1, wherein the noble metal is palladium.

### Claim 3 (depends on 1)

A process according to claim 1, wherein ammonia is present in the reaction mixture in an amount of 1 to 30 times the stoichiometric amount.

### Claim 4 (depends on 1)

A process according to claim 1, wherein the pressure is 10 to 200 bars.

### Claim 5 (depends on 1)

A process according to claim 1, wherein reaction is conducted at a temperature of 10.degree. to 150.degree. C.

### Claim 6 (depends on 1)

A process according to claim 1, wherein the alkali metal salt is lithium.

### Claim 7 (depends on 1)

A process according to claim 1, wherein thereafter the so-prepared alkali metal salt of d,l-phenylalanine is converted to the free acid by contacting the salt with an acid.

### Claim 8 (depends on 1)

A process according to claim 1, wherein
a. the noble metal is palladium
b. the temperature is 20.degree.-80.degree. C.
c. the pressure is 10-100 bar.

### Claim 9 (depends on 6)

A process according to claim 6, wherein
a. the noble metal is palladium b. the temperature is 20.degree.-80.degree. C.
c. the pressure is 10-100 bar.

### Claim 10 (depends on 8)

A process according to claim 8, wherein the reaction is carried out for between two and six hours.

### Claim 11 (depends on 9)

A process according to claim 9, wherein the reaction is carried out for between two and six hours.