5-Chloro-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxylic Acid

In a 500 ml flask, 6.0 g (31 mmol) of 5-chloro-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carbaldehyde are added to 30 ml of toluene. A solution of 2.4 g (62 mmol) of sodium hydroxide in 6 ml of water is added to the reaction mixture, followed by 103 ml of a 30percent solution of hydrogen peroxide in water, whilst keeping the temperature below 37° C. After the end of the addition, the reaction mixture is stirred at 50° C. for 7 hours. Once the reaction mixture is back to room temperature, the two phases are separated and the organic phase is extracted with 100 ml of water. The combined aqueous phases are acidified to pH 2 with aqueous hydrochloric acid. The resulting white precipitate is filtered, washed twice with 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. In 1000 mL reaction flask, 38.9g 3- difluoromethyl-1-methyl-5-chloro-4-carbaldehyde and 390ml of water, 8.4g of sodium hydroxide was added, followed by stirring, 1g of nano copper oxide, control of the reaction temperature is 25-30 ° C, air through an oxidation reaction 15 hours, starting material HPLC i.e.3- difluoromethyl-1-methyl-5-chloro-4-carbaldehyde , less than the total amount of an amount of 0.2percent; the reaction was stopped by filtration, recovery of copper catalyst. The reaction mixture was cooled to below 10 ° C, add 31percent hydrochloric acid to a pH of 1-2, the precipitated solid was filtered; the solid was washed with a small amount of water; and dried to give the product 3-methyl-5-fluoro-1- chloro-pyrazole-4-carboxylic acid 40g, HPLC content 99percent; LC-MS: m / e = 210.In a 500 ml flask, 6.0 g (31 mmol) of 5-chloro-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carbaldehyde are added to 30 ml of toluene. A solution of 2.4 g (62 mmol) of sodium hydroxide in 6 ml of water is added to the reaction mixture, followed by 103 ml of a 30percent solution of hydrogen peroxide in water, whilst keeping the temperature below 37° C. After the end of the addition, the reaction mixture is stirred at 50° C. for 7 hours. Once the reaction mixture is back to room temperature, the two phases are separated and the organic phase is extracted with 100 ml of water. The combined aqueous phases are acidified to pH 2 with aqueous hydrochloric acid. The resulting white precipitate is filtered, washed twice with 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. In 1000 mL reaction flask, 38.9g 3- difluoromethyl-1-methyl-5-chloro-4-carbaldehyde and 390ml of water, 8.4g of sodium hydroxide was added, followed by stirring, 1g of nano copper oxide, control of the reaction temperature is 25-30 ° C, air through an oxidation reaction 15 hours, starting material HPLC i.e.3- difluoromethyl-1-methyl-5-chloro-4-carbaldehyde , less than the total amount of an amount of 0.2percent; the reaction was stopped by filtration, recovery of copper catalyst. The reaction mixture was cooled to below 10 ° C, add 31percent hydrochloric acid to a pH of 1-2, the precipitated solid was filtered; the solid was washed with a small amount of water; and dried to give the product 3-methyl-5-fluoro-1- chloro-pyrazole-4-carboxylic acid 40g, HPLC content 99percent; LC-MS: m / e = 210.

Molecular Weight:210.56
XLogP3:1.4
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:5
Rotatable Bond Count:2
Exact Mass:210.0007614
Monoisotopic Mass:210.0007614
Topological Polar Surface Area:55.1
Heavy Atom Count:13
Complexity:217
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes