Process for the preparation of phenyl pyrazole compounds
A process for the preparation of compound (III) which comprises the reaction between a compound of general formula (V) and dicyano acetylene (IV), said reaction carried out in the presence of water wherein R is selected from CF 3 , or C 1 to C 6 alkyl M is an alkaline or alkaline-earth metal or silver.
1. Novel compound according to general formula (III)
wherein R is CF 3 .
2. A process for the preparation of compound (VII) which comprises a first step of reaction of an aryl hydrazine of compound (I) with a compound of general formula (III) to produce an intermediate compound of general formula (VI), and a second step which comprises the oxidation of the compound (VI), according to the reaction scheme below
where R is selected from CF 3 or C 1 to C 6 alkyl.
3. A process as claimed in claim 2 wherein the compound of formula (VI) is 1-trifluoromethyl thio 2-(2,6-dichloro-4-trifluoromethyl phenylhydrazino) succinonitrile.
4. A process as claimed in claim 2 carried out in the presence of a polar solvent selected from tetrahydrofuran N-methylpyrrolidone, N,N-dimethylformamide and dimethylsulphoxide.
5. A process as claimed in claim 2 carried out in the presence of a catalyst selected from N-benzyltrimethylammonium hydroxide, or alanine.
6. A process as claimed in claim 2 carried out at a temperature of from 0 to about 150° C.
7. A process as claimed in claim 2 wherein the molar ratio of the compound of formula (III) to the compound of formula (I) is from 1:10 to 10:1.
8. A process as claimed in claim 2 wherein the second step is carried out in the presence of a quinone, a peroxide,a hypohalite or an alkali metal hydroxide.
9. A process as claimed in claim 2 wherein the second step is carried out in the presence of air and optionally a metal salt or oxide.
10. A process as claimed in claim 2 wherein the second step is carried out in the presence of an aromatic halogenated or non-halogenated hydrocarbon solvent.
11. A process as claimed in claim 2 wherein the second step is carried out at a temperature of from 20 to 150° C.
12. Novel compound according to general formula (VI)
wherein R is CF 3 .
13. A process as claimed in claim 3 carried out in the presence of a polar solvent selected from tetrahydrofuran, N-methylpyrrolidone, N,N-dimethylformamide and dimethylsulphoxide.