Methanol → Methyl 1-(difluoromethyl)-1H-pyrazole-3-carboxylate
Reaktionsgleichung
[F:1][CH:2]([F:11])[N:3]1[CH:7]=[CH:6][C:5]([C:8]([OH:10])=[O:9])=[N:4]1.S(=O)(=O)(O)O.[CH3:17]O>>[CH3:17][O:9][C:8]([C:5]1[CH:6]=[CH:7][N:3]([CH:2]([F:1])[F:11])[N:4]=1)=[O:10]Komponenten
4
Reaktionsbedingungen
- Temperatur
- 23 °C
Versuchsvorschrift
A solution of 1-difluoromethyl-1H-pyrazole-3-carboxylic acid (CAS [925179-02-8]) (500 mg, 3.1 mmole) in methanol (18 ml) was cooled to 0° C. and treated with sulfuric acid (98%, 0.2 ml, 3.1 mmol). The mixture was heated to reflux for 2 hours, cooled to 23° C. and concentrated at reduced pressure. The residue was partitioned between AcOEt and water, the organic layer was washed with water until the water phase showed a neutral pH, dried and evaporated to give the title compound (535 mg) as a colorless liquid which was used without further purification. MS: m/z=177.1 [M+H]+.