Hydrochloric Acid → 3-(Difluoromethyl)-1-methyl-1H-pyrazole-4-carboxylic acid

Temperature

60 °C

A mixture of ethyl 3-difluoromethyl-1-methyl-1H-pyrazol-4-ylcarboxylate (1.4 g, 52 mmol) and aqueous sodium hydroxide solution (10% strength, 3.1 g, 8 mmol) was stirred at 60° C. for 2 h. The reaction mixture was cooled to room temperature, and the pH was then adjusted to 1 using concentrated hydrochloric acid. The reaction mixture was cooled further to 0° C., resulting in the precipitation of a solid. The precipitated solid was filtered off, washed with cyclohexane and dried under reduced pressure. This gave 3-difluoromethyl-1-methyl-1H-pyrazol-4-ylcarboxylic acid as a solid (amount: 0.8 g; yield: 87%). 1H-NMR (DMSO-d6): δ=3.9 (s, 2H), 7.2 (t, 1H), 8.35 ppm (s, 1H).

1. temperatureThe reaction mixture was cooled to room temperature
2. temperatureThe reaction mixture was cooled further to 0° C.
3. customresulting in the precipitation of a solid
4. filtrationThe precipitated solid was filtered off
5. washwashed with cyclohexane
6. customdried under reduced pressure

ORD record

ord-afdef79e2b7c4a6cb6ef667062a66e76

Source dataset

uspto-grants-2012_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08314233B2