5-CHLORO-1-METHYL-3-(TRIFLUOROMETHYL)PYRAZOLE-4-CARBOXALDEHYDE synthesis

Yield:-

Reaction Conditions:

with sodium hydroxide;trichlorophosphate in N,N-dimethyl-formamide

Steps:

1 Synthesis of 1-methyl-3-trifluoromethyl-5-chloropyrazole-4-carboxylic acid
1) 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 solution 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.

References:

Nissan Chemical Industries, Ltd. US6063734, 2000, A