# US 2014/0155620 A1 · Fipronil production process

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2014/0155620 A1
- Document ID: US20140155620A1
- Status: Published application
- Kind: A1
- Application number: 14/174,406
- Filed: 2014-02-06
- Published: 2014-06-05
- Earliest claimed: 2010-07-12
- Assignees: Irvita Plant Protection, A Branch of Celsius Property B.V
- Applicants: Irvita Plant Protection, A Branch of Celsius Property B.V.
- Inventors: Anat LEVIN; Michael GRABARNICK
- Web page: https://patentgrep.com/patent/US20140155620A1

## CPC

- C07D 231/44: Oxygen and nitrogen or sulfur and nitrogen atoms
- A61P 33/14: Ectoparasiticides, e.g. scabicides
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)
- A61P: SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS

## Abstract

An improved oxidation process for preparing 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-trifluoromethylsulphinyl-pyrazole, of formula (I) is described. The process includes admixing 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-trifluoromethylthiopyrazole of formula (II) with dichloroacetic acid and hydrogen peroxide in the presence of a strong acid.

## Claims

### Claim 1

A process for preparing 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-trifluoromethylsulphinyl-pyrazole, fipronil, of formula (I)
wherein the process comprises:
admixing 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-trifluoromethylthiopyrazole of formula (II)
with dichloroacetic acid and hydrogen peroxide in the presence of a strong acid;
quenching the reaction mixture;
isolating the compound of formula (I); and optionally purifying the obtained compound of formula (I).

### Claim 2 (depends on 1)

The process according to claim 1 which further comprises organic solvent selected from monochlorobenzene, polychlorobenzene, toluene, xylene, ethyl acetate, butyl acetate, acetonitrile, N-methylpyrrolidone (NMP) and dimethylacetamide (N,N-DMA), or a combination thereof.

### Claim 3 (depends on 1)

The process according to claim 1, wherein said strong acid is selected from sulfuric acid, methanesulfonic acid, and p-toluenesulfonic acid, or a combination thereof.

### Claim 4 (depends on 1)

The process according to claim 1, wherein the process is conducted at a temperature in the range of from about 0° C. to about 40° C.

### Claim 5 (depends on 1)

The process according to claim 1, which comprises in situ preparation of the oxidizing agent.

### Claim 6 (depends on 4)

The process according to claim 4, wherein the hydrogen peroxide is added to the reaction mixture over a period of from 30 minutes to about 120 minutes.

### Claim 7 (depends on 1)

The process according to claim 1, wherein the oxidizing agent is added to the reaction mixture over a period of from 30 minutes to about 240 minutes.

### Claim 8 (depends on 1)

The process of claim 1, wherein the reaction mixture is quenched by adding a quenching agent selected from the group consisting of sodium metabisulfite, sodium sulfite, sodium thiosulfate and buffers such as phosphate buffer (NaH2PO4/Na2HPO4), carbonate buffer (NaHCO3/NaCO3) and acetate buffer (CH3CO2H/CH3CO2Na), or a combination thereof.

### Claim 9 (depends on 1)

The process according to claim 1, wherein the compound of formula (I) has a purity of at least 95%.