US2688024A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of 3-pyrazolidones
Assignee: Ilford Imaging UK Ltd
•
Filing: 1952-10-06
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Granted: 1954-08-31
•
Expires: 1972-10-06
Abstract
No abstract record available.
Inventors
- 👤 Kendall John David
- 👤 Duffin George Frank
- 👤 Axford Anthony Joseph
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 19:59
CPC Classifications
C; C07; C07D; C07D231/00; C07D231/02; C07D231/06; C07D231/08
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
50 words
A PROCESS FOR THE PRODUCTION OF 3-PYRAZOLIDONES WHICH COMPRISES HEATING, UNDER ANHYDROUS CONDITIONS AND IN THE PRESENCE OF A BASIC CONDENSING AGENT, A HYDRAZINE OF THE GENERAL FORMULA RNH,NH2 WHRE R IS SELECTED FROM THE CLASS CONSISTING OF PHENYL, ALKYLPHENYL AND HALOGENOPHENYL GROUPS, WITH AN ESTER OF THE GENERAL FORMULA:
Claim 2
Dependent Claim
50 words
A PROCESS FOR THE PRODUCTION OF 3-PYRAZOLIDONES WHICH COMPRISES HEATING, UNDER ANHYDROUS CONDITIONS AND IN THE PRESENCE OF A BASIC CONDENSING AGENT, A HYDRAZINE OF THE GENERAL FORMULA RNH,NH2 WHRE R IS SELECTED FROM THE CLASS CONSISTING OF PHENYL, ALKYLPHENYL AND HALOGENOPHENYL GROUPS, WITH AN ESTER OF THE GENERAL FORMULA:
References Cited (Backward Citations)
US2289367A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1957-08-30 | 1958-03-01 | 1958-08-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-08-30 | 1962-03-01 | 1962-08-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-08-30 | 1966-03-01 | 1966-08-31 | $7700.00 | Window Closed / Lapsed |