Dimethylformamide → 5-Chloro-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carbaldehyde

Participants

Reaction Conditions

Reaction Steps

To DMF (40.84 g, 0.56 mol) was added POCl3 (104.4 mL, 1.12 mol) at 0° C. After 30 min, to the resulting Vilsmier reagent was added 3-(difluoromethyl)-1-methyl-1H-pyrazol-5-ol from step 1 above (69.1 g, 0.46 mol), and the mixture was heated at 80° C. for 16 h. Then reaction was diluted with dichloromethane (400 mL), and treated with a solution of potassium carbonate (780 g) in water (2 L) at 0° C. The organic layer was separated, and the aqueous layer extracted with dichloromethane (3×100 mL). The combined organic extracts were washed with water (500 mL), passed through a layer of silica gel (10×10 cm), and evaporated. The residue was crystallized from ether (100 mL) and hexane (100 mL) to give 69 g (77%) of the title product.

Provenance & Evidence