# US 4,398,043 A · Process for preparing cyclopentenolones

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- Number: US 4,398,043 A
- Document ID: US4398043A
- Status: Granted
- Kind: A
- Application number: 06/324,135
- Filed: 1981-11-23
- Granted: 1983-08-09
- Earliest claimed: 1980-12-10
- Assignees: Sumitomo Chemical Company, Limited
- Inventors: Kenji Saito; Yukihisa Takisawa; Hiroshi Yamachika
- Web page: https://patentgrep.com/patent/US4398043A

## CPC

- C07C 45/59: in five-membered rings (from ozonides C07C45/40)
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

A process for preparing cyclopentenolones of the formula: ##STR1## wherein R.sub.1 is a straight, branched or cyclic alkyl group having not more than 6 carbon atoms, a straight, branched or cyclic alkenyl group having not more than 6 carbon atoms, a straight or branched alkynyl group having not more than 6 carbon atoms or a group of the formula: ##STR2## wherein R.sub.2 is a hydrogen atom, a methyl group or a halogen atom directly from the corresponding furan-carbinols of the formula: ##STR3## wherein R.sub.1 is as defined above in a single step with an excellent yield, characterized in that the furan-carbinols are treated with water in the presence or absence of a catalyst.

## Claims

### Claim 1

A one step process for preparing cyclopentenolones consisting essentially of treating a furan-carbinol of the formula: ##STR11## wherein R.sub.1 is a straight, branched or cyclic alkyl group having not more than 6 carbon atoms, a straight, branched or cyclic alkenyl group having not more than 6 carbon atoms, a straight or branched alkynyl group having not more than 6 carbon atoms or a group of the formula: ##STR12## wherein R.sub.2 is a hydrogen atom, a methyl group or a halogen atom in an aqueous medium in the presence or absence of a catalyst to obtain the corresponding cyclopentenolone of the formula: ##STR13## wherein R.sub.1 is as defined above.

### Claim 2 (depends on 1)

The process according to claim 1, wherein the reaction temperature is from 60.degree. to 200.degree. C.

### Claim 3 (depends on 1, 2)

The process according to claim 1 or 2, wherein the pH value of the aqueous medium is from 3 to 8.

### Claim 4 (depends on 1)

The process according to claim 1, wherein the treatment is effected in the presence of a catalyst chosen from a metal salt and a surfactant.