Reaction #1909815

Reaction equation

sodium hydroxide

1-methyl-3-trifluoromethyl-5-pyrazolone

phosphorus oxychloride

DMF

→

1-methyl-3-trifluoromethyl-5-chloropyrazole-4-carbaldehyde

Yield 77.0%

Conditions

Workup

1. 1
   Otherwas returned to room temperature
2. 2
   workup.STIRRINGstirred for 7 hours
3. 3
   workup.WAITAfter having been left
4. 4
   Otherto be at 70° C.
5. 5
   workup.ADDITIONadded
6. 6
   Otherprecipitated crystals
7. 7
   Filtrationwere taken out through filtration
8. 8
   Otherdried

Procedure

21.35 g of phosphorus oxychloride was dropwise added to 4.72 g of DMF at 10° C. or lower. After the temperature of the reaction solutio was returned to room temperature, the reaction mixture was stirred for 1 hour, and 10.71 g of 1-methyl-3-trifluoromethyl-5-pyrazolone was added thereto. The resulting mixture was heated up to 110° C., and stirred for 7 hours. After having been left to be at 70° C., the reaction mixture was poured into ice water. After pH of the mixture was made to be about 4 with an aqueous solution of sodium hydroxide added thereto, and precipitated crystals were taken out through filtration and dried to obtain 10.55 g of 1-methyl-3-trifluoromethyl-5-chloropyrazole-4-carbaldehyde.

Source