US2830996A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Resolution of dl-pyrrolidonecarboxylic acid
Assignee: International Minerals and Chemical Corp
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Filing: 1955-07-28
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Granted: 1958-04-15
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Expires: 1975-07-28
Abstract
No abstract record available.
Inventors
- 👤 Vassel Bruno
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:39
CPC Classifications
C; C07; C07D; C07D207/00; C07D207/02; C07D207/18; C07D207/22; C07D207/24; C07D207/26; C07D207/273; C07D207/277; C07D207/28
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
67 words
A PROCESS FOR RESOLVING DL-PYRROLIDONECARBOXYLIC ACID WHICH COMPRISES REACTING DL-PYRROLIDONECARBOXYLIC ACID WITH AN OPTICALLY ACTIVE FORM OF A C1-C7 ALKYL ESTER OF TYROSINE IN SOLUTION IN A LOWER ALKANOL, FRACTIONALLY CRYSTALLIZING THEREFROM A SALT OF SAID ESTER AND PYRROLIDONECARBOXYLIC ACID OF THE OPPOSITE OPTICAL CONFIGURATION FROM SAID ESTER, SEPARATING SAID SALT FROM THE SOLUTION, DECOMPRISING SAID SALT, AND RECOVERING SAID PYRROLIDONECARBOXYLIC ACID OF OPPOSITE OPTICAL CONFIGURATION THEREFROM.
Claim 2
Dependent Claim
67 words
A PROCESS FOR RESOLVING DL-PYRROLIDONECARBOXYLIC ACID WHICH COMPRISES REACTING DL-PYRROLIDONECARBOXYLIC ACID WITH AN OPTICALLY ACTIVE FORM OF A C1-C7 ALKYL ESTER OF TYROSINE IN SOLUTION IN A LOWER ALKANOL, FRACTIONALLY CRYSTALLIZING THEREFROM A SALT OF SAID ESTER AND PYRROLIDONECARBOXYLIC ACID OF THE OPPOSITE OPTICAL CONFIGURATION FROM SAID ESTER, SEPARATING SAID SALT FROM THE SOLUTION, DECOMPRISING SAID SALT, AND RECOVERING SAID PYRROLIDONECARBOXYLIC ACID OF OPPOSITE OPTICAL CONFIGURATION THEREFROM.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-04-14 | 1961-10-14 | 1962-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-04-14 | 1965-10-14 | 1966-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-04-14 | 1969-10-14 | 1970-04-15 | $7700.00 | Window Closed / Lapsed |