Patent US3899508A successfully refreshed from Google Patents.
US3899508A
Expired / Lapsed
US
⏱️ 0.0 years remaining
5-(2-Aminophenyl)pyrazole-3-carboxylic acids and esters thereof
Assignee: Eli Lilly and Co
•
Filing: 1974-04-12
•
Granted: 1975-08-12
•
Expires: 1994-04-12
Abstract
Abstract 5-(2-Aminophenyl)pyrazole-3-carboxylic acids, useful as intermediates in the preparation of compounds useful as complement inhibitors, are prepared by reacting a 2nitroacetophenone with a dialkyl oxalate in the presence of a strong base and in an inert solvent to give the corresponding alkyl 2-nitrobenzoylpyruvate, condensing the alkyl 2nitrobenzoylpyruvate with hydrazine in an inert solvent to give an alkyl 5-(2-nitrophenyl)-pyrazole-3-carboxylate, reducing the nitro group catalytically to give the alkyl 5-(2aminophenyl)pyrazole-3-carboxylate, and, if desired, hydrolyzing the ester to the free acid.
Inventors
- 👤 James H Wikel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:03
CPC Classifications
C; C07; C07C; C07C205/00; C07C205/49; C07C205/56; C07D; C07D231/00; C07D231/02; C07D231/10; C07D231/14
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
5 words
A COMPOUND OF THE FORMULA,
Claim 2
Dependent Claim
5 words
A COMPOUND OF THE FORMULA,
Claim 3
Dependent Claim
10 words
The compound of claim 1, wherein R1 is C1-C3 alkyl.
References Cited (Backward Citations)
CA535564A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-11 | 1979-02-10 | 1979-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-11 | 1983-02-10 | 1983-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-11 | 1987-02-10 | 1987-08-12 | $7700.00 | Window Closed / Lapsed |