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US4100347A
Expired / Lapsed
US
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3,4-Dihydro-2-methyl-4-oxo-2H-1,2-benzothiazine-3-carboxylic acid-1,1-dioxide
Assignee: Pfizer Inc
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Filing: 1976-06-10
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Granted: 1978-07-11
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Expires: 1996-06-10
Abstract
Abstract Process for production of 3,4-dihydro-2-methyl-4-oxo-2H-1,2-benzothiazine-3-carboxylic acid-1,1-dioxide by hydrolysis, in the presence of hydroxide ions, of an alkyl or aralkyl ester thereof followed by precipitation of the acid at pH below 6.0 and its use as an intermediate for the production of N-(2-pyridyl)-3,4-dihydro-2-methyl-4-oxo-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide and the analogous N-(2-thiazolyl)-compound, effective antiinflammatory agents.
Inventors
- 👤 Philip D. Hammen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:54
CPC Classifications
C; C07; C07D; C07D279/00; C07D279/02
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
3 words
Crystalline 3,4-dihydro-2-methyl-4-oxo-2H-1,2-benzothiazine-3-carboxylic acid-1,1-dioxide.
Claim 2
Dependent Claim
3 words
Crystalline 3,4-dihydro-2-methyl-4-oxo-2H-1,2-benzothiazine-3-carboxylic acid-1,1-dioxide.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-07-10 | 1982-01-09 | 1982-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-07-10 | 1986-01-09 | 1986-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-07-10 | 1990-01-09 | 1990-07-11 | $7700.00 | Window Closed / Lapsed |