Patent US3732255A successfully refreshed from Google Patents.
US3732255A
Expired / Lapsed
US
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Process for optical resolution of o-acetylpantolactone
Assignee: Daiichi Pharmaceutical Co Ltd
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Filing: 1969-09-30
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Granted: 1973-05-08
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Expires: 1989-09-30
Abstract
Abstract OPTICALLY RESOLVING A MIXTURE OF D(-)-O-ACETYLPANTOLACTONE AND L(+)-O-ACETYLPANTOLACTONE BY SEEDING A HOMOGENEOUS LIQUID MIXTURE OF THESE TWO MATERIALS WITH OPTICALLY ACTIVE SEED CRYSTALS OF EITHER OF THE TWO ENANITIOMERS IN A BINARY SYSTEM. THE SAME ISOMER AS THE SEED CRYSTALS IS CRYSTALLIZED AND THE PRECIPITATE CAN BE RECOVERED.
Inventors
- 👤 S Nabeta
- 👤 I Kuniyoshi
- 👤 M Inagaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 09:55
CPC Classifications
C; C07; C07D; C07D307/00; C07D307/02; C07D307/26; C07D307/30; C07D307/32; C07D307/33; H; H02; H02G; H02G9/00; H02G9/02
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) | 1976-05-07 | 1976-11-06 | 1977-05-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-07 | 1980-11-06 | 1981-05-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-07 | 1984-11-06 | 1985-05-08 | $7700.00 | Window Closed / Lapsed |