反应详情

温度

0 °C

3.0 g of 2-methyl-3-methylsulfinyl-4-trifluoromethylbenzoic acid and 1.25 g of 3-hydroxy-2-methylpyrazole are suspended in 20 ml of ethyl acetate and 4.8 g of pyridine under an inert atmosphere and cooled to −25° C. with stirring. 1.51 g of thionyl chloride are then slowly added dropwise such that the temperature always remains below −20° C. Following the complete addition of the thionyl chloride, the mixture is stirred for a further 20 minutes. 40 μl of cold water, 10 ml of ethyl acetate and a further 10 ml of water are added, and the mixture is heated to 0° C. After separating the organic phase from the aqueous phase, the aqueous phase is extracted twice with 5 ml of ethyl acetate in each case. The combined organic phases are dried, giving 3.69 g of (5-hydroxy-1-methyl-1H-pyrazol-4-yl)[2-methyl-3-(methylsulfinyl)-4-(trifluoromethyl)phenyl]methanone (90.7% yield).

1. stirringthe mixture is stirred for a further 20 minutes
2. customAfter separating the organic phase from the aqueous phase
3. extractionthe aqueous phase is extracted twice with 5 ml of ethyl acetate in each case
4. customThe combined organic phases are dried