Patent US3658811A successfully refreshed from Google Patents.
US3658811A
Expired / Lapsed
US
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Process for the optical resolution of mixtures of l- and d-alpha-amino-epsilon-caprolactam
Assignee: Teijin Ltd
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Filing: 1969-12-03
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Granted: 1972-04-25
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Expires: 1989-12-03
Abstract
Abstract PROCESS FOR THE OPTICAL RESOLUTION OF A MIXTURE OF L- AND D-A-AMINO-E-CAPROLACTAMS BY TREATING THE MIXTURE WITH AN OPTICALLY ACTIVE N-BENZOYL- OR N-PARANITROBENZOYL-GLUTAMIC ACID IN AN AQUEOUS MEDIUM OR ALCOHOLIC MEDIUM. IN THIS WAY, L- OR D-A-AMINO-E-CAPROLACTAM IN A PURE FORM CAN BE OBTAINED AT HIGH YIELDS.
Inventors
- 👤 Ikuzo Tanaka
- 👤 Yasuhisa Ohno
- 👤 Tadashi Okada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 19:35
CPC Classifications
C; C07; C07D; C07D223/00; C07D223/02; C07D223/06; C07D223/12; F; F23; F23D; F23D5/00; F23D5/02; F23D5/04
Claims Analysis
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-04-25 | 1975-10-25 | 1976-04-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-04-25 | 1979-10-25 | 1980-04-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-04-25 | 1983-10-25 | 1984-04-25 | $7700.00 | Window Closed / Lapsed |