反应详情

A solution of 0.05 mol of 4-methylisoxazole-4-carbonyl chloride (7.3 g) in 20 ml of acetonitrile is added dropwise, at room temperature, to a solution of 0.1 mol of 4-trifluoromethylaniline (16.1 g) in 150 ml of acetonitrile. After stirring for 20 minutes, the precipitated 4-trifluoromethylaniline hydrochloride is filtered off with suction and washed twice with 20 ml of acetonitrile on each occasion, and the combined filtrates are concentrated under reduced pressure. Yield: 12.8 g of white, crystalline N-(4-trifluoromethylphenyl)-5-methylisoxa-zole-4-catboxamide (leflunomide).

1. filtrationthe precipitated 4-trifluoromethylaniline hydrochloride is filtered off with suction
2. washwashed twice with 20 ml of acetonitrile on each occasion
3. concentrationthe combined filtrates are concentrated under reduced pressure