Hydrogen Peroxide → 5-Chloro-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxylic acid

Temperature

50 °C

In a 500 ml flask, 6.0 g (31 mmol) of 5-chloro-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carbaldehyde were added to 30 ml of toluene. A solution of 2.4 g (62 mmol) of sodium hydroxide in 6 ml of water was added to the reaction mixture, followed by 103 ml of a 30% solution of hydrogen peroxide in water, whilst keeping the temperature below 37° C. After the end of the addition, the reaction mixture was stirred at 50° C. for 7 hours. Once the reaction mixture was back to room temperature, the two phases were separated and the organic phase was extracted with 100 ml of water. The combined aqueous phases were acidified to pH 2 with aqueous hydrochloric acid. The resulting white precipitate was filtered, washed with 2*20 ml of water, and dried to yield 3.2 g of 5-chloro-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxylic acid as a white solid.

1. customthe temperature below 37° C
2. additionAfter the end of the addition
3. customwas back to room temperature
4. customthe two phases were separated
5. extractionthe organic phase was extracted with 100 ml of water
6. filtrationThe resulting white precipitate was filtered
7. washwashed with 2*20 ml of water
8. customdried

ORD record

ord-8d468c5a76cd4191909e9c68969bb5ea

Source dataset

uspto-grants-2014_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08772266B2