Dimethylformamide → 5-Chloro-3-(4-chlorophenyl)-1-phenyl-1H-pyrazole-4-carbaldehyde

Participants

Reaction Steps

At 5° to 40° 284 g of phosphorus oxytrichloride are added dropwise during a period of 90 minutes to 270 g of dimethylformamide. Stirring is carried out for 30 minutes at 15° and then 100 g of 3-p-chlorophenyl-1-phenyl-2-pyrazoline-5-one are added. Heating is carried out for 1.5 hours at 50° and for 21 hours at 70°. The product is poured on to 2 kg of ice, the pH is adjusted to 3-4 with 20 % of sodium hydroxide and the precipitate is filtered off. 5-Chloro-3-p-chlorophenyl-1-phenyl-pyrazole-4-carboxaldehyde is obtained with a yield of 99 %; F 169.5°-171° (from acetone).

Provenance & Evidence