Phosphorus oxychloride → 5-Chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde

Participants

Reaction Conditions

Reaction Steps

A solution containing 1.0 g of 5-methyl-2-phenyl-2H-pyrazol-3-ol (commercially available e.g. Aldrich M7,080-0) and 2.1 ml of phosphorus oxychloride in 10 ml of anhydrous N,N-dimethylformamide was stirred under nitrogen at 100° C. for 4 h. The mixture was poured into 70 ml of saturated sodium hydrogen carbonate and extracted three times with 60 ml of dichloromethane. The combined extracts were dried over magnesium sulphate, filtered and evaporated. The residue was purified by chromatography on silica gel using dichloromethane/methanol for the elution to give 177 mg of 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde as yellow needles.

Provenance & Evidence