US3663556A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for preparing alkali metal salts of 3-hydroxy -2-oxo-1(2h)-pyridine-sulfonic acid
Assignee: Novartis Corp
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Filing: 1970-08-19
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Granted: 1972-05-16
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Expires: 1990-08-19
Abstract
Abstract ALKALI METAL SALTS OF 3-HYDROXY2-OXO-1(2H)-PYRIDINESULFONIC ACID ARE PREPARED FROM FURFURAL, A CHLORINATING AGENT, SULFAMINIC ACID AND AN ALKALI METAL ION-DONATING AGENT.
Inventors
- 👤 John Valdemar Brammer Petersen
- 👤 Niels Clauson-Kaas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 05:37
CPC Classifications
C; C07; C07D; C07D213/00; C07D213/02; C07D213/04; C07D213/60; C07D213/62; C07D213/69; C07D213/63; C07D213/65; C07D213/72; C07D213/73; C07D213/76; C07D213/89; C09; C09B; C09B29/00; C09B29/34; C09B29/36; C09B29/3604; C09B29/3617; C09B29/3621; C09B29/3626
Claims Analysis
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References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-16 | 1975-11-15 | 1976-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-16 | 1979-11-15 | 1980-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-16 | 1983-11-15 | 1984-05-16 | $7700.00 | Window Closed / Lapsed |