US3798259A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Synthesis of ypsilon-ketoesters
Assignee: F Hoffmann La Roche AG
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Filing: 1973-04-09
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Granted: 1974-03-19
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Expires: 1993-04-09
Abstract
Abstract ALKANOYL PROPIONATES OF THE FORMULA R-CH2-C(=O)-CH2-CH2-C(=O)-O-R'' WHEREIN R AND R'' ARE EACH LOWER ALKYL ARE PREPARED FROM THE CORRESPONDING ALKANOYL SUCCINATES BY TREATMENT WITH BORIC ACID. THESE COMPOUNDS ARE USEFUL IN THE PREPARATION OF 2-ALKYL-CYCLOPENTAN-1,3-DIONES WHICH ARE VALUABLE INTERMEDIATES IN THE SYNTHESIS OF NATURAL PRODUCTS PARTICULARLY STEROIDS.
Inventors
- 👤 P Wehrli
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:31
CPC Classifications
C; C07; C07C; C07C67/00; C07C49/00; C07C49/385; C07C49/395; C07C69/00; C07C69/66; C07C69/67; C07C69/716
Claims Analysis
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-18 | 1977-09-17 | 1978-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-18 | 1981-09-17 | 1982-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-18 | 1985-09-17 | 1986-03-19 | $7700.00 | Window Closed / Lapsed |