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US3991077A
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Method of racemizing optically active N-acylamino acids
Assignee: Ajinomoto Co Inc
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Filing: 1975-03-03
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Granted: 1976-11-09
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Expires: 1995-03-03
Abstract
Abstract Optically active amino acids N-acylated with carboxylic acids are readily racemized without decomposition at elevated temperature in inert organic solvents in which they are homogeneously soluble at the racemization temperature. When the deacylated amino acid is insoluble or only sparingly soluble in the solvent, the method permits a convenient work-up of the products of enzymatic deacylation of one enantiomorph of the N-acylamino acid in which the remaining enantiomorph is racemized for recycling to the deacylation step.
Inventors
- 👤 Teruo Uzuki
- 👤 Mayumi Takahashi
- 👤 Misa Noda
- 👤 Yoshioki Komachiya
- 👤 Hachiro Wakamatsu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 08:15
CPC Classifications
C; C12; C12P; C12P41/00; C12P41/006; C12P41/007; C12P13/00; C12P13/04
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
149 words
A method of thermally racemizing an optically active enantiomorph of an N-acylamino acid which comprises: a. mixing said enantiomorph with a solvent selected from the group consisting of 1. a triester of phosphoric acid with an alkanol or haloalkanol having up to eight carbon atoms, phenol, halophenol, or lower-alkyl-phenol, 2. a di-lower-alkylformamide, 3. a di-lower-alkylsulfoxide, and 4. a di-lower-alkylketone; and b. holding the resulting mixture at a temperature between 90° and 200° C until said enantiomorph is substantially completely racemized to the corresponding N-acyl-DL-amino-acid, 1. the acyl of said N-acylamino acid being lower alkanoyl, halo-lower-alkanoyl, benzoyl, or halobenzoyl, 2. said lower alkanoyl and lower alkyl having one to four carbon atoms, 3. said halo being chloro, bromo, or iodo, 4. the weight of said solvent in said mixture being sufficient homogeneously to dissolve said enantiomorph at said temperature, but not greater than seven times the weight of said enantiomorph.
Claim 2
Independent Claim
149 words
A method of thermally racemizing an optically active enantiomorph of an N-acylamino acid which comprises: a. mixing said enantiomorph with a solvent selected from the group consisting of 1. a triester of phosphoric acid with an alkanol or haloalkanol having up to eight carbon atoms, phenol, halophenol, or lower-alkyl-phenol, 2. a di-lower-alkylformamide, 3. a di-lower-alkylsulfoxide, and 4. a di-lower-alkylketone; and b. holding the resulting mixture at a temperature between 90° and 200° C until said enantiomorph is substantially completely racemized to the corresponding N-acyl-DL-amino-acid, 1. the acyl of said N-acylamino acid being lower alkanoyl, halo-lower-alkanoyl, benzoyl, or halobenzoyl, 2. said lower alkanoyl and lower alkyl having one to four carbon atoms, 3. said halo being chloro, bromo, or iodo, 4. the weight of said solvent in said mixture being sufficient homogeneously to dissolve said enantiomorph at said temperature, but not greater than seven times the weight of said enantiomorph.
Claim 3
Dependent Claim
25 words
A method as set forth in claim 1, wherein said enantiomorph is an N-acyl derivative of phenylalanine, aspartic acid, methionine, valine, dimethoxyphenylalanine, leucine, or tryptophan.
Claim 4
Dependent Claim
16 words
A method as set forth in claim 2, wherein said acyl is acetyl, formyl, or benzoyl.
Claim 5
Dependent Claim
22 words
A method as set forth in claim 3, wherein said solvent is triethyl phosphate, tributyl phosphate, tri-2-chloroethyl phosphate, dimethylsulfoxide, dimethylformamide, or methylethylketone.
Claim 6
Dependent Claim
48 words
A method as set forth in claim 1, wherein said enantiomorph prior to said mixing is produced by exposing the optically inactive form of said N-acylamino acid to acylase in an aqueous medium until the antipode of said enantiomorph is converted to the corresponding optically active amino acid.
Claim 7
Dependent Claim
60 words
A method as set forth in claim 5, wherein the interaction of said acylase with said inactive form results in an aqueous solution of said enantiomorph and of said optically active amino acid, said solvent is not more than sparingly soluble in water, and said mixing includes extracting said aqueous solution with said solvent while said aqueous solution is acidic.
Claim 8
Dependent Claim
59 words
A method as set forth in claim 5, wherein the interaction of said acylase with said inactive form results in an aqueous solution of said enantiomorph and of said optically active amino acid, the water is removed from said solution having an optically active free N-acyl amino acid, and said mixing includes extracting the resulting residue with said solvent.
Claim 9
Dependent Claim
21 words
A method as set forth in claim 1, wherein said resulting mixture consists essentially of said enantiomorph and of said solvent.
Claim 10
Dependent Claim
23 words
A method as set forth in claim 8, wherein the N-acylamino group of said enantiomorph is bound directly to an asymmetric carbon atom.
References Cited (Backward Citations)
US3458568A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-11-09 | 1980-05-10 | 1980-11-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-11-09 | 1984-05-10 | 1984-11-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-11-09 | 1988-05-10 | 1988-11-09 | $7700.00 | Window Closed / Lapsed |