反应详情

At 0° C., a solution of 38.9 g 3-difluoromethyl-1-methyl-1H-pyrazole-4-carbonyl chloride (0.2 mol) in 100 ml dichloromethane is added dropwise to a stirred solution of 15 g alaninol (0.2 mol) and 25 g triethylamine (0.25 mol) in 400 ml dichloromethane. The reaction mixture is stirred for 1 h at ambient temperature and then allowed to stand for 3 h at ambient temperature. After removal of the solvent the residue is purified by flash chromatography over silica gel 400 g (eluent: ethyl acetate/methanol 19:1). 42 g (90% of theory) of 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid (2-hydroxy-1-methyl-ethyl)-amide is obtained in form of a solid (mp. 81-87° C.).

1. waitto stand for 3 h at ambient temperature
2. customAfter removal of the solvent the residue
3. customis purified by flash chromatography over silica gel 400 g (eluent: ethyl acetate/methanol 19:1)