Reaction #51142

Reaction equation

N-[3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)pyrazole-5-yl]pyrazine-2-carboxamide

phosphorus pentachloride

→

1-(2,6-dichloro-4-trifluoromethylphenyl)-5-(pyrazin-2-ylchloromethylimino)pyrazole-3-carbonitrile

Yield 79.0%

Solvents

toluene

Conditions

Workup

1. 1
   Temperaturewas heated
2. 2
   Temperatureunder reflux for 2 hours
3. 3
   Temperatureby heating
4. 4
   Temperatureunder reflux for 1 hour
5. 5
   Filtrationcrystals were filtrated
6. 6
   Washwashed with toluene
7. 7
   workup.DISSOLUTIONThe crystals were dissolved in 1 L of chloroform
8. 8
   Extractionthe solution was extracted
9. 9
   workup.ADDITIONafter the addition of water
10. 10
    WashThe organic layer was washed twice with water
11. 11
    Dryingwith saturated saline, and then, dried over anhydrous sodium sulfate
12. 12
    OtherThe solvent was removed by distillation
13. 13
    Washthe resulting crystals were washed with hexane

Procedure

A mixture of 139 g (0.33 mol) of N-[3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)pyrazole-5-yl]pyrazine-2-carboxamide, 72.6 g (0.35 mol) of phosphorus pentachloride, and 300 ml of toluene was heated under reflux for 2 hours. Further, 5 g of phosphorus pentachloride was added thereto, followed by heating under reflux for 1 hour. The mixture was cooled to room temperature and allowed to stand overnight. After stirring for 30 minutes, crystals were filtrated and washed with toluene. The crystals were dissolved in 1 L of chloroform and the solution was extracted after the addition of water. The organic layer was washed twice with water, and with saturated saline, and then, dried over anhydrous sodium sulfate. The solvent was removed by distillation and the resulting crystals were washed with hexane to obtain 112.3 g (yield 79%) of 1-(2,6-dichloro-4-trifluoromethylphenyl)-5-(pyrazin-2-ylchloromethylimino)pyrazole-3-carbonitrile.

Source