US4013680A
Expired / Lapsed
US
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Process for the preparation of aromatic α-keto carboxylic acids
Assignee: Glaxo Laboratories Ltd
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Filing: 1975-06-18
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Granted: 1977-03-22
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Expires: 1995-06-18
Abstract
Abstract A process is described for the preparation of aryl α-keto acids in which the corresponding methyl ketone or aldehyde is oxidized in aqueous solution with an inorganic nitrite salt and hydrochloric or sulfuric acid.
Inventors
- 👤 Martin Godfrey Johnson
- 👤 John Peter Turnbull
- 👤 Harold Alfred Crisp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 12:59
CPC Classifications
C; C07; C07D; C07D333/00; C07D333/02; C07D333/04; C07D333/06; C07D333/24; C07C; C07C51/00; C07C51/16; C07C51/27; C07D307/00; C07D307/02; C07D307/34; C07D307/38; C07D307/54
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
127 words
A process for the preparation of an α-keto acid of the formula R.CO.COOH in which R is selected from the group consisting of phenyl, thienyl, furyl and benzofuryl, which process comprises oxidizing in a first stage the corresponding methyl ketone of the formula R.CO.CH 3 in aqueous solution with an inorganic nitrite salt and hydrochloric or sulphuric acid, raising the pH to about 1.5 to 2.5 and completing the oxidation in a second stage by adding more of said nitrite salt to the reaction mixture, said process being carried out at a temperature of 40°-100° C with from 2-3 moles nitrite salt per mole ketone being added in said first stage and from 1.5-2.5 moles nitrite salt per mole of ketone being added in said second stage.
Claim 2
Dependent Claim
127 words
A process for the preparation of an α-keto acid of the formula R.CO.COOH in which R is selected from the group consisting of phenyl, thienyl, furyl and benzofuryl, which process comprises oxidizing in a first stage the corresponding methyl ketone of the formula R.CO.CH 3 in aqueous solution with an inorganic nitrite salt and hydrochloric or sulphuric acid, raising the pH to about 1.5 to 2.5 and completing the oxidation in a second stage by adding more of said nitrite salt to the reaction mixture, said process being carried out at a temperature of 40°-100° C with from 2-3 moles nitrite salt per mole ketone being added in said first stage and from 1.5-2.5 moles nitrite salt per mole of ketone being added in said second stage.
Claim 3
Dependent Claim
16 words
A process as claimed in claim 1 wherein R is a phenyl, thienyl or furyl group.
Claim 4
Dependent Claim
19 words
A process as claimed in claim 1 wherein the nitrite is an alkali metal or alkaline earth metal nitrite.
Claim 5
Dependent Claim
15 words
A process as claimed in claim 3 wherein the nitrite is sodium or potassium nitrite.
Claim 6
Dependent Claim
16 words
A process as claimed in claim 1 wherein the reaction temperature is 60° to 95° C.
Claim 7
Dependent Claim
14 words
A process as claimed in claim 1 wherein the nitrite salt is added steadily.
Claim 8
Dependent Claim
13 words
A process as claimed in claim 1 wherein the acid is hydrochloric acid.
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) | 1980-03-21 | 1980-09-20 | 1981-03-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-03-21 | 1984-09-20 | 1985-03-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-03-21 | 1988-09-20 | 1989-03-22 | $7700.00 | Window Closed / Lapsed |