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Patent US3769281A successfully refreshed from Google Patents.
US3769281A
Expired / Lapsed
US
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Deblocking process for cephalosporin antibiotics
Assignee: Eli Lilly and Co
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Filing: 1970-07-09
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Granted: 1973-10-30
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Expires: 1990-07-09
Abstract
Abstract IN THE PREPARATION OF CEPHALOSPORINS (LIKE CEPHALEXIN) CONTAINING AN AMINO FUNCTION THAT IS PROTECTED DURING ACYLATION BY A TERTIARY-BUTOXYCARBONYL GROUP, THE PROTECTING GROUP IS REMOVED BY TREATMENT OF THE ACYLATION PRODUCT WITH PARATOLUENESULFONIC ACID MONOHYDRATE IN ACETONITRILE, NITROMETHENE, OR CHLOROFORM.
Inventors
- 👤 R Chauvette
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 21:02
CPC Classifications
C; C07; C07D; C07D501/00; C07D501/14; C07D501/16; C07D501/20; C07D501/22; C07D501/02; C07D501/04
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) | 1976-10-29 | 1977-04-30 | 1977-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-29 | 1981-04-30 | 1981-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-29 | 1985-04-30 | 1985-10-30 | $7700.00 | Window Closed / Lapsed |