US3843728A
Expired / Lapsed
US
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Racemic-diketone compounds
Assignee: F Hoffmann La Roche AG
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Filing: 1973-01-17
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Granted: 1974-10-22
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Expires: 1993-01-17
Abstract
Abstract This invention is directed to racemic-diketone compounds of the formula: WHEREIN R1 and R2 are lower alkyl, araklyl and taken together form a lower alkylene radical and R3 and R4 are lower alkyl, aralkyl, and taken together form a lower alkylene radical; useful in a stereoselective synthesis of the food additive mesonordigydroguaiaretic acid from a protected ortho dihydroxy benzene.
Inventors
- 👤 C Perry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 00:40
CPC Classifications
C; C07; C07D; C07D307/00; C07D307/02; C07D307/34; C07D307/38; C07D307/40; C07D307/42; C07C; C07C43/00; C07C43/02; C07C43/20; C07C43/205; C07C43/2055; C07C45/00; C07C45/45; C07C45/46; C07C45/61; C07C45/63; C07C45/67; C07C45/68; C07C45/72; C07C49/00; C07C49/76; C07C49/84; C07D307/04; C07D307/10; C07D307/12
Claims Analysis
Total Claims: 4
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
15 words
The compound in accordance with claim 1 wherein R1, R2, R3 and R4 are methyl.
Claim 4
Dependent Claim
13 words
The compound in accordance with claim 1 wherein said compound is racemic 2,3-dimethyl-1,4-bis(3,4-dimethoxyphenyl)1,4-butanedione.
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) | 1977-10-21 | 1978-04-22 | 1978-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-21 | 1982-04-22 | 1982-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-21 | 1986-04-22 | 1986-10-22 | $7700.00 | Window Closed / Lapsed |