Dimethylformamide → 1-Phenyl-3-(trifluoromethyl)-1H-pyrazole-5-carbonyl chloride

Participants

Reaction Steps

A sample of crude 1-phenyl-3-(trifluoromethyl)pyrazole-5-carboxylic acid (4.13 g, 16.1 mmol) was dissolved in methylene chloride (45 mL). The solution was treated with oxalyl chloride (1.80 mL, 20.6 mmol), followed by N,N-dimethylformamide (0.010 mL, 0.13 mmol). Off-gassing began shortly after adding the N,N-dimethylformamide catalyst. The reaction mixture was stirred for ˜20 minutes under ambient conditions, then was heated to reflux for a period of 35 minutes. Volatiles were removed by stripping the reaction mixture on a rotary evaporator at a bath temperature of 55° C. The product consisted of 4.43 g of a light-yellow oil. The only impurity observed by 1H NMR was N,N-dimethylformamide.

Provenance & Evidence