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US3931322A
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Synthesis of 2-alkyl-cyclopentan-1,3-diones
Assignee: Hoffmann La Roche Inc
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Filing: 1974-01-25
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Granted: 1976-01-06
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Expires: 1994-01-25
Abstract
Abstract 2-Lower alkyl-cyclopentan-1,3-diones are prepared in high yield by cyclization of gamma-ketoesters in the presence of a colloidal suspension of an alkali metal primary lower alcoholate.
Inventors
- 👤 Urs Oskar Hengartner
- 👤 Pius Anton Wehrli
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 11:32
CPC Classifications
C; C07; C07C; C07C45/00; C07C45/45; C07C45/455
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
59 words
A process for the preparation of a compound of the formula ##SPC3## wherein R 1 is lower alkyl, which comprises treating a compound of the formula ##SPC4## wherein R 1 and R 2 are each lower alkyl, with a colloidal suspension of an alkali metal primary lower alkyl alcoholate in an inert organic solvent medium, at an elevated temperature.
Claim 2
Dependent Claim
59 words
A process for the preparation of a compound of the formula ##SPC3## wherein R 1 is lower alkyl, which comprises treating a compound of the formula ##SPC4## wherein R 1 and R 2 are each lower alkyl, with a colloidal suspension of an alkali metal primary lower alkyl alcoholate in an inert organic solvent medium, at an elevated temperature.
Claim 3
Dependent Claim
15 words
The process of claim 1 wherein the alkali metal primary lower alcoholate is sodium methoxide.
Claim 4
Dependent Claim
19 words
The process of claim 1 wherein R 1 is methyl, that is, the compound of formula I is 2-methyl-cyclopentan-1,3-dione.
Claim 5
Dependent Claim
19 words
The process of claim 1 wherein R 1 is ethyl, that is, the compound of formula I is 2-ethyl-cyclopentan-1,3-dione.
Claim 6
Dependent Claim
26 words
The process of claim 1 wherein the inert organic solvent medium is selected from the group consisting of aliphatic hydrocarbons, benzene hydrocarbons and substituted benzene hydrocarbons.
Claim 7
Dependent Claim
10 words
The process of claim 5 wherein the solvent is xylene.
Claim 8
Dependent Claim
37 words
The process of claim 1 wherein the colloidal suspension of alkali metal primary lower alcoholate is prepared by addition of a concentrated solution of said alcoholate in its correspondong alcohol to the solvent medium at about reflux.
Claim 9
Dependent Claim
28 words
The process of claim 1 wherein the solvent medium contains between about 0.1 and 2.0 equivalents of a polar aprotic cosolvent, relative to the compound of formula II.
Claim 10
Dependent Claim
16 words
The process of claim 8 wherein between about 0.2 and 0.5 equivalents of cosolvent are utilized.
Claim 11
Dependent Claim
12 words
The process of claim 8 wherein the polar aprotic cosolvent is dimethylsulfoxide.
Claim 12
Dependent Claim
20 words
The process of claim 1 wherein between about 1 and 5.0 equivalents of alkali metal primary lower alcoholate are utilized.
Claim 13
Dependent Claim
21 words
The process of claim 11 wherein between about 1 and 2.5 equivalents of alkali metal primary lower alkyl alcoholate are utilized.
Claim 14
Dependent Claim
14 words
The process of claim 1 wherein the temperature is between about 80° and 250°C.
Claim 15
Dependent Claim
19 words
The process of claim 13 wherein the reaction temperature is at about the reflux point of the solvent medium.
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) | 1979-01-05 | 1979-07-07 | 1980-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-05 | 1983-07-07 | 1984-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-05 | 1987-07-07 | 1988-01-06 | $7700.00 | Window Closed / Lapsed |