Process for preparing pesticidal intermediates
View Patent ↗A process for preparing pesticides or pesticidal intermediates, particularly 5-amino-1 aryl-3-cyanopyrazoles, having the formula said process comprising reacting a compound having the formula with a cyanide salt.
1. A process for the preparation of a compound having the formula:
wherein:
W is —CR 4 ;
R 1 is halogen, haloalkyl, haloalkoxy, R 5 S(O) n — or —SF 5 ;
R 2 is hydrogen or halogen;
R 3 is hydrogen or R 6 S(O) m —;
R 4 is halogen;
each of R 5 and R 6 is alkyl or haloalkyl; and
each of m and n is 0, 1 or 2;
said process comprising reacting a compound having the formula:
wherein R 1 , R 2 , R 3 and W are as defined above, R 7 is a leaving group and R 8 is chlorine or bromine, with a cyanide salt.
2. A process according to claim 1 , wherein the cyanide salt is an alkali metal cyanide, an alkaline earth metal cyanide or ammonium cyanide.
3. A process according to claim 2 , wherein the cyanide salt is potassium cyanide or sodium cyanide.
4. A process according to claim 1 , which is conducted in a solvent selected from the group consisting of nitriles, amides, sulfoxides, ethers and alcohols, optionally in the presence of water.
5. A process according to claim 4 , wherein the solvent comprises acetonitrile, N-methylpyrrolidinone, dimethylsulfoxide, tetrahydrofuran or ethanol.
6. A process according to claim 2 , which is conducted in a solvent selected from the group consisting of nitriles, amides, sulfoxides, ethers and alcohols, optionally in the presence of water.
7. A process according to claim 6 , wherein the solvent comprises acetonitrile, N-methylpyrrolidinone, dimethylsulfoxide, tetrahydrofuran or ethanol.
8. A process according to claim 1 , wherein from 2 to 5 molar equivalents of cyanide are employed.
9. A process according to claim 2 , wherein from 2 to 5 molar equivalents of cyanide are employed.
10. A process according to claim 4 , wherein from 2 to 5 molar equivalents of cyanide are employed.
11. A process according to claim 6 , wherein from 2 to 5 molar equivalents of cyanide are employed.
12. A process according to claim 1 , wherein the reaction temperature is from about −20° C. to the reflux temperature of the solvent.
13. A process according to claim 12 , wherein the reaction temperature is from about 0° C. to about 20° C.
14. A process according to claim 1 , wherein R 7 is chlorine or bromine.
15. A process according to claim 2 , wherein R 7 is chlorine or bromine.
16. A process according to claim 9 , wherein R 7 is chlorine or bromine.
17. A process according to claim 1 , wherein:
R 1 is trifluoromethyl, trifluoromethoxy or —SF 5 ;
each of R 2 and R 4 is chlorine or bromine;
R 3 is hydrogen or R 6 S(O) m —;
R 6 is optionally halogenated methyl or ethyl; and
each of R 7 and R 8 is chlorine.
18. A process according to claim 2 , wherein:
R 1 is trifluoromethyl, trifluoromethoxy or —SF 5 ;
each of R 2 and R 4 is chlorine or bromine;
R 3 is hydrogen or R 6 S(O) m —;
R 6 is optionally halogenated methyl or ethyl; and
each of R 7 and R 8 is chlorine.
19. A process according to claim 4 , wherein:
R 1 is trifluoromethyl, trifluoromethoxy or —SF 5 ;
each of R 2 and R 4 is chlorine or bromine;
R 3 is hydrogen or R 6 S(O) m —;
R 6 is optionally halogenated methyl or ethyl; and
each of R 7 and R 8 is chlorine.
20. A process according to claim 6 , wherein:
R 1 is trifluoromethyl, trifluoromethoxy or —SF 5 ;
each of R 2 and R 4 is chlorine or bromine;
R 3 is hydrogen or R 6 S(O) m —;
R 6 is optionally halogenated methyl or ethyl; and
each of R 7 and R 8 is chlorine.
21. A process according to claim 8 , wherein:
R 1 is trifluoromethyl, trifluoromethoxy or —SF 5 ;
each of R 2 and R 4 is chlorine or bromine;
R 3 is hydrogen or R 6 S(O) m —;
R 6 is optionally halogenated methyl or ethyl; and
each of R 7 and R 8 is chlorine.
22. A process according to claim 17 , wherein:
R 1 is trifluoromethyl;
each of R 2 , R 4 , R 7 and R 8 is chlorine; and
R 3 is hydrogen.
23. A process according to claim 1 , wherein the compound of formula (I) is:
5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)pyrazole;
5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-trifluoromethylthiopyrazole;
5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-trifluoromethylsulfinylpyrazole; or
5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)-4-ethylsulfinylpyrazole.
24. A process according to claim 1 , wherein the intermediate having the formula:
wherein R 1 , R 2 , R 3 and W are as defined in claim 1 , which is formed in the course of the reaction, cyclizes under the conditions of the reaction to afford the corresponding compound of formula (I).
25. A process according to claim 1 , wherein the intermediate having the formula:
wherein R 1 , R 2 , R 3 and W are as defined in claim 1 , which is formed in the course of the reaction, is cyclized in the presence of base to afford the corresponding compound of formula (I).