Patent US1799428A successfully refreshed from Google Patents.
Patent US2843598A successfully refreshed from Google Patents.
US2843598A
Expired / Lapsed
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Process for preparing 3-pyrazolidones
Assignee: Eastman Kodak Co
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Filing: 1956-10-22
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Granted: 1958-07-15
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Expires: 1976-10-22
Abstract
No abstract record available.
Inventors
- 👤 Thomas S Donovan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 12:45
CPC Classifications
C; C07; C07D; C07D231/00; C07D231/02; C07D231/06; C07D231/08
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
28 words
THE PROCESS FOR THE PREPARATION OF 1-PHENYL-4,4DIMETHYL-3-PYRAZOLIDONE WHICH COMPRISES HEATING B-HYDROXYPIVALYLPHENYLHYDRAZIDE AT A TEMPERATURE LESS THAN ABOUT 110*C. IN THE PRESENCE OF PHOSPHORIC ACID AS A CYCLODEHYDRATION CATALYST.
Claim 2
Dependent Claim
28 words
THE PROCESS FOR THE PREPARATION OF 1-PHENYL-4,4DIMETHYL-3-PYRAZOLIDONE WHICH COMPRISES HEATING B-HYDROXYPIVALYLPHENYLHYDRAZIDE AT A TEMPERATURE LESS THAN ABOUT 110*C. IN THE PRESENCE OF PHOSPHORIC ACID AS A CYCLODEHYDRATION CATALYST.
References Cited (Backward Citations)
US2743279A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-07-14 | 1962-01-13 | 1962-07-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-07-14 | 1966-01-13 | 1966-07-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-07-14 | 1970-01-13 | 1970-07-15 | $7700.00 | Window Closed / Lapsed |