Patent US3591579A successfully refreshed from Google Patents.
US3591579A
Expired / Lapsed
US
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Resolution of amino-caprolactams
Assignee: Sanyo Chemical Industries Ltd
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Filing: 1968-08-13
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Granted: 1971-07-06
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Expires: 1988-08-13
Abstract
Abstract A MIXTURE OF D- AND L-A-AMINO-E-CAPROLACTAMS IS RESOLVED INTO ITS ENANTIMORPHS BY CONVERTING THE MIXTURE, E.G. AS THE DL-AMINOLACTAM, INTO THE SALTS WITH CERTAIN SPECIFIC SULFONIC ACIDS, MORE ESPECIALLY WITH B-NAPHTHALENE-1-SULFONIC ACID OR WITH 2-NAPHTHY AMINO-1-SULFONIC ACID, AND THEN RESOLVING THE SALTS INTO THE OPTICALLY ACTIVE ISOMERS BY CRYSTALLIZING FROM A SUPERSATURATED SOLUTION THEREOF IN A SOLVENT (WATER OR WATER-MISCIBLE ORGANIC SOLVENT).
Inventors
- 👤 Yasuo Shibahara
- 👤 Motoyuki Suzuki
- 👤 Yoshihiro Hayashi
- 👤 Toshiro Fukuda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:24
CPC Classifications
C; C07; C07D; C07D223/00; C07D223/02; C07D223/06; C07D223/12
Claims Analysis
Total Claims: 0
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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) | 1974-07-05 | 1975-01-04 | 1975-07-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-07-05 | 1979-01-04 | 1979-07-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-07-05 | 1983-01-04 | 1983-07-06 | $7700.00 | Window Closed / Lapsed |