反应详情

A solution of 6.00 g (20.4 mmol) of diethyl 1-methyl-4-(trifluoromethyl)-1H-pyrazole-3,5-dicarboxylate in 80 ml of tetrahydrofuran is admixed under argon at −78° C. with 38.9 ml (42.8 mmol) of a 1.1M solution of diisobutylaluminium hydride in cyclohexane and stirred overnight at this temperature. The reaction mixture is admixed with water and extracted twice with ethyl acetate. The organic phase is dried over sodium sulphate, filtered over silica gel and concentrated by evaporation in vacuo. Chromatographic purification on silica gel gives 4.10 g of ethyl 3-(hydroxymethyl)-1-methyl-4-(trifluoromethyl)-1H-pyrazole-5-carboxylate (80%).

1. extractionextracted twice with ethyl acetate
2. dry with materialThe organic phase is dried over sodium sulphate
3. filtrationfiltered over silica gel
4. concentrationconcentrated by evaporation in vacuo
5. customChromatographic purification on silica gel