Patent US4677437A successfully refreshed from Google Patents.
US4289879A
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Synthetic method and intermediate for piroxicam
Assignee: Pfizer Inc
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Filing: 1980-09-29
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Granted: 1981-09-15
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Expires: 2000-09-29
Abstract
Abstract 2-Methoxyethyl 4-hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxylate 1,1-dioxide is an advantageous ester precursor for piroxicam (4-hydroxy-2-methyl-N-2-pyridyl-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide), an antiinflammatory agent established in medical practice.
Inventors
- 👤 Joseph G. Lombardino
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 03:07
CPC Classifications
C; C07; C07D; C07D275/00; C07D275/04; C07D275/06; C07D279/00; C07D279/02
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
6 words
A compound of the formula ##STR10##
Claim 2
Dependent Claim
6 words
A compound of the formula ##STR10##
Claim 3
Dependent Claim
33 words
A process for converting an ester of the formula ##STR11## to piroxicam which comprises reacting said ester with 2-aminopyridine in a reaction-inert organic solvent at 115°-175° C. until the reaction is substantially complete.
Claim 4
Dependent Claim
33 words
A process for converting an ester of the formula ##STR11## to piroxicam which comprises reacting said ester with 2-aminopyridine in a reaction-inert organic solvent at 115°-175° C. until the reaction is substantially complete.
Claim 5
Dependent Claim
10 words
A process of claim 2 wherein the solvent is xylene.
Claim 6
Dependent Claim
19 words
A process of claim 2 or 3 wherein byproduct 2-methoxyethanol is removed by codistillation with solvent during the reaction.
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) | 1984-09-14 | 1985-03-16 | 1985-09-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-09-14 | 1989-03-16 | 1989-09-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-09-14 | 1993-03-16 | 1993-09-15 | $7700.00 | Window Closed / Lapsed |