# US 4,393,243 A · Carotenoid intermediate by an oxidation process

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- Number: US 4,393,243 A
- Document ID: US4393243A
- Status: Granted
- Kind: A
- Application number: 06/244,574
- Filed: 1981-03-17
- Granted: 1983-07-12
- Earliest claimed: 1981-03-17
- Assignees: Hoffmann-La Roche Inc.
- Inventors: Bruno Lohri
- Web page: https://patentgrep.com/patent/US4393243A

## CPC

- C07C 403/16: not being part of —CHO groups
- C07B 2200/09: Geometrical isomers
- C07C 2601/16: the ring being unsaturated
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07B: GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR (preparation of carboxylic acid esters by telomerisation C07C67/47; telomerisation C08F)

## Abstract

A process for synthesizing 3,5,5-trimethyl-4-[(E)-3-oxo-1-butenyl]-2-cyclohexen-1-one which is a known intermediate in a process for preparing a carotenoid.

## Claims

### Claim 1

A process for the manufacture of 3,5,5-trimethyl-4-[(E)-3-oxo-1-butenyl]-2-cyclohexen-1-one of the formula ##STR3## which process comprises oxidizing .alpha.-ionone of the formula ##STR4## in a reaction mixture containing concentrated acetic acid with oxygen or an oxygen-containing gas in the presence of a cobalt acetate/bromide catalyst.

### Claim 2 (depends on 1)

A process according to claim 1, wherein the reaction mixture contains at most about 1 weight percent of water.

### Claim 3 (depends on 1)

A process according to claim 1, wherein the reaction mixture contains at most about 0.7 weight percent of water.

### Claim 4 (depends on 1)

A process according to claim 1, wherein the acetic acid is glacial acetic acid.

### Claim 5 (depends on 1)

A process according to claim 1, wherein the reaction mixture further contains an inert organic-solvent.

### Claim 6 (depends on 5)

A process according to claim 5, wherein the inert organic solvent is selected from the group consisting of a ketone, an ester, dioxan, a saturated hydrocarbon and an inert aromatic solvent.

### Claim 7 (depends on 6)

A process according to claim 6, wherein the inert organic solvent is acetone, ethyl methyl ketone, diethyl ketone, ethyl acetate, isopropyl acetate, n-butyl acetate or cyclohexane.

### Claim 8 (depends on 7)

A process according to claim 7, wherein the inert organic solvent is cyclohexane and the cyclohexane/acetic acid volume ratio is about 1:1.

### Claim 9 (depends on 1)

A process according to claim 1, wherein the bromide ion-forming substance is selected from a group consisting of acetyl bromide, hydrogen bromide, sodium bromide and ammonium bromide.

### Claim 10 (depends on 1)

A process according to claim 1 wherein the cobalt salt to bromide ion-forming substance is in a molar ratio of at least about 0.5:1.

### Claim 11 (depends on 10)

A process according to claim 10, wherein said ratio is about 1:1.

### Claim 12 (depends on 1)

A process according to claim 1, wherein the cobalt acetate is in an amount of at least about 10 mole percent of the .alpha.-ionone concentration.

### Claim 13 (depends on 12)

A process according to claim 12, wherein said mole percent is 20.

### Claim 14 (depends on 1)

A process according to claim 1, wherein the oxygen-containing gas is an oxygen and nitrogen mixture which contains about 10 percent to about 50 percent by volume oxygen.

### Claim 15 (depends on 14)

A process according to claim 14, wherein said mixture contains about 20 percent to about 40 percent oxygen by volume.

### Claim 16 (depends on 1)

A process according to claim 1, wherein the oxidation is carried out at a temperature of about 30.degree. C. to about 80.degree. C.

### Claim 17 (depends on 1)

A process according to claim 1, wherein the oxidation is carried out at a temperature of at most the reflux temperature of the reaction mixture.

### Claim 18 (depends on 16)

A process according to claim 16, wherein the oxidation is carried out at a temperature of about 35.degree. C. to about 65.degree. C.

### Claim 19 (depends on 18)

A process according to claim 18, wherein the temperature is about 40.degree. C. to about 55.degree. C.