Patent US3972789A successfully refreshed from Google Patents.
US2676992A
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Method of making vitamin a and intermediates formed thereby
Assignee: Eastman Kodak Co
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Filing: 1951-09-11
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Granted: 1954-04-27
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Expires: 1971-09-11
Abstract
No abstract record available.
Inventors
- 👤 Wilbert J Humphlett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 13:31
CPC Classifications
C; C07; C07C; C07C403/00; C07C403/06; C07C403/08; C07C403/12; C07C403/14; C07C2601/00; C07C2601/12; C07C2601/16
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
26 words
THE METHOD OF MAKING CITAMIN A WHICH COMPRISES REACTING A DIALKYL ACETAL OF ACETOACETALDEHYDE WITH AN ACETYLIDE AND THEREBY FORMING AN ACETYLENIC CARBINOL OF THE FORMULA
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) | 1957-04-26 | 1957-10-26 | 1958-04-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-04-26 | 1961-10-26 | 1962-04-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-04-26 | 1965-10-26 | 1966-04-27 | $7700.00 | Window Closed / Lapsed |