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Process for the preparation of fipronil and analogues thereof

A technology for fipronil and a compound, which is applied in the field of preparing 5-amino-3-cyano-1--4-trifluoromethylsulfinylpyrazole, can solve the problem of difficult industrial application, difficult to scale up, and a Therapeutic use, etc.

Inactive Publication Date: 2011-02-09
VETOQUINOL SA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0018] They are difficult to scale up and thus not easy for industrial application;
[0019] They are intended for the preparation of insecticidally active compounds for use in agriculture or horticulture and, therefore, the quality of the product, especially its purity, is not necessarily suitable for therapeutic use;

Method used

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  • Process for the preparation of fipronil and analogues thereof
  • Process for the preparation of fipronil and analogues thereof
  • Process for the preparation of fipronil and analogues thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0135] Example 1 - Industrial Scale Purification of CF 3 SO 2 Na

[0136] In a 500L reactor, add 75.0kg of commercially available CF 3 SO 2 Na, followed by the addition of 210 kg of ethyl acetate. The resulting mixture was stirred at 25±5°C for 1 hour. Silica gel (10.7 kg) was added. The resulting mixture was stirred for 15 minutes, then centrifuged. The filter cake (residue) was placed in a 200 L reactor and 76.3 kg of ethyl acetate was added. The resulting mixture was stirred at 25±5°C for 1 hour, and then subjected to centrifugation. The filter cake (residue) was put back into the reactor and the process (ethyl acetate and filtration) was repeated one more time using 76.3 kg of ethyl acetate. The washing process is repeated 2 to 3 times.

[0137] The filtrates were combined, and 106.6 kg of pure deionized water was added. The resulting mixture was heated to 50±5°C and stirred at this temperature for 30 minutes, then cooled to room temperature. The organic layer w...

Embodiment 2

[0138] Embodiment 2-industrial scale prepares catalyst PTSA-NHMe 2

[0139] In a 200 L reactor, 70.0 kg PTSA was added. Add Me dropwise at 25±5°C 2 NH (5805 g, 30% in water). The resulting solution was stirred at this temperature for 1 hour. The solution was then concentrated under vacuum at 70±5°C. Toluene (100.0 kg) was added to the residue; the remaining water was removed by azeotropic distillation under vacuum at 70±5°C. When water could no longer be separated, the mixture was cooled to 20±5°C and filtered through a 1.0 mm porous titanium alloy filter cartridge under a pressurized nitrogen purge. The filter cake was dried under vacuum at 70±5°C.

Embodiment 3

[0140] Embodiment 3-industrial scale preparation formula I compound

[0141] In a 200L reactor, add 12.0kg 5-amino-1-(2,6-dichloro-4-(trifluoromethyl)phenyl)-1H-pyrazole-3-carbonitrile (compound of formula III), 11.7kg The CF obtained in Example 1 3 SO 2 The catalyst PTSA.NHMe that obtains in Na, 12.4kg embodiment 2 2 and 90.8kg toluene. The resulting mixture was stirred at room temperature (25±5° C.) for 15 minutes, then 0.11 kg of DMF was added. The resulting mixture was stirred at room temperature for 30 minutes. Allow the mixture to cool to 0±2 °C and add PCl dropwise at this temperature 3 (5.1g). The resulting mixture was stirred at 0±2°C for 1 hour. It was then allowed to warm to room temperature and stirred at 20±5°C for 1 hour. The mixture was then heated to about 65°C to 70°C and stirred at this temperature for 8 hours.

[0142] Water (48.0 kg) and 16.1 kg ethyl acetate were added. The resulting mixture was stirred for 30 minutes, cooled at room temperature ...

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Abstract

The present invention relates to a new and efficient process for preparing 5-amino-1-(2,6-dichloro-4-(trifluoromethyl)phenyl)-4-(trifluoromethylthio)-IH-pyrazole-3-carbonitrile (hereinafter referred to as compound of formula I), which is useful as an intermediate for the antiparasitic agent fipronil, and a process for preparing 5-amino-3-cyano-l-(2,6-dichloro-4-trifluoromethylphenyl)-4-trifluoromethyl sulfinylpyrazole (hereinafter referred to as compound of formula II or fipronil). In one aspect, there is provided a process for preparing fipronil comprising: a) a step of reacting CF3S(=O)ONa with the compound of formula (III) in the presence of a reducing / halogenating agent; and b) a step of oxidizing the compound of formula (I) obtained in step a) in the presence of a selective oxidizing agent, under suitable conditions, wherein the selective oxidizing agent selectively effects oxidation of (I) to the corresponding sulfoxide, Fipronil. In certain exemplary embodiments, the selective oxidizing agent is MHSO5, wherein M is an alkaline metal cation.

Description

[0001] priority [0002] This application claims priority to U.S. Provisional Patent Application No. 61 / 014,769, filed December 19, 2007, and French Patent Application No. FR 08 / 50084, filed January 8, 2008; the entire contents of these applications are hereby incorporated by reference enter here. technical field [0003] The present invention relates to a novel and effective preparation of 5-amino-1-(2,6-dichloro-4-(trifluoromethyl)phenyl)-4-(trifluoromethylthio)-1H-pyrazole- The method of 3-nitrile (hereinafter referred to as formula I compound), this compound can be used as the intermediate of antiparasitic drug fipronil, and the present invention also relates to the preparation of 5-amino-3-cyano-1-(2,6 - the method of dichloro-4-trifluoromethylphenyl)-4-trifluoromethylsulfinylpyrazole (hereinafter referred to as compound of formula II or fipronil). [0004] [0005] Specifically, the compound of structural formula (II) can be prepared as follows: in such as PCl 3 or...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D231/44
CPCC07D231/44A61P33/00A61P33/10
Inventor 杨登贵埃里希·威德默
Owner VETOQUINOL SA
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