Patent US3983162A successfully refreshed from Google Patents.
US3983162A
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Optical resolution of alkyl esters of DL-phenylalanine
Assignee: Nutrasweet Co
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Filing: 1975-01-02
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Granted: 1976-09-28
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Expires: 1995-01-02
Abstract
Abstract Treatment of an alkyl ester of DL-phenylalanine with an N-acyl-D-phenylalanine results in the formation of the corresponding insoluble salt of L-phenylalanine alkyl ester and N-acyl-D-phenylalanine. The salt is purified by recrystallization in the presence of an added quantity of the alkyl ester of DL-phenylalanine or the alkyl ester of L-phenylalanine. The isolated, purified salt is decomposed to afford the desired L-phenylalanine alkyl ester, which is an important starting material in the preparation of artificial sweetening agents.
Inventors
- 👤 James M. Schlatter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:47
CPC Classifications
C; C07; C07C; C07C233/00; C07C233/01; C07C233/45; C07C233/46
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
52 words
In a process for the production of L-phenylalanine alkyl ester from the corresponding DL-phenylalanine alkyl ester by resolving with an N-acyl-D-phenylalanine, the improvement which comprises recrystallizing in an inert solvent the crude salt of N-acyl-D-phenylalanine and L-phenylalanine alkyl ester in the presence of the corresponding DL-phenylalanine alkyl ester or L-phenylalanine alkyl ester.
Claim 2
Dependent Claim
52 words
In a process for the production of L-phenylalanine alkyl ester from the corresponding DL-phenylalanine alkyl ester by resolving with an N-acyl-D-phenylalanine, the improvement which comprises recrystallizing in an inert solvent the crude salt of N-acyl-D-phenylalanine and L-phenylalanine alkyl ester in the presence of the corresponding DL-phenylalanine alkyl ester or L-phenylalanine alkyl ester.
Claim 3
Dependent Claim
40 words
The improvement as in claim 1 wherein the salt comprises compounds represented by the following formula ##STR2##wherein R 1 is lower alkyl having 1-4 carbon atoms inclusive and R 2 is hydrogen or lower alkyl having 1-7 carbon atoms inclusive.
Claim 4
Dependent Claim
26 words
The improvement as in claim 1, wherein the salt comprises N-acetyl-D-phenylalanine and L-phenylalanine methyl ester and the recrystallization is in the presence of DL-phenylalanine methyl ester.
Claim 5
Dependent Claim
26 words
The improvement as in claim 1, wherein the salt comprises N-acetyl-D-phenylalanine and L-phenylalanine methyl ester and the recrystallization is in the presence of L-phenylalanine methyl ester.
References Cited (Backward Citations)
US3832388A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-09-28 | 1980-03-29 | 1980-09-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-28 | 1984-03-29 | 1984-09-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-28 | 1988-03-29 | 1988-09-28 | $7700.00 | Window Closed / Lapsed |