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US 2017/0320832 A1Published application
Fipronil production process
AssigneeAdama Makhteshim Ltd.
InventorsAnat Levin, Michael Grabarnick
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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.
Claims10
A method for the preparation of the compound having the following general formula (I):
- wherein R1 and R2 are chlorine;
- through oxidation of a compound having the general formula (II) in the presence of dichloroacetic acid, of an oxidizing agent, and of a strong acid:
- wherein R1 and R2 are defined as above, where the oxidizing agent is hydrogen peroxide, and where the strong acid is sulfuric acid.
The method according to claim I, wherein the temperature at which oxidation takes place is 15° C.
Dependencies are inferred from the claim text.