Formaldehyde → 5-Difluoromethoxy-4-hydroxymethyl-1-phenyl-3-trifluoromethylpyrazole

Participants

Reaction Steps

22.8 g (0.10 mole) of the 5-hydroxy-1-phenyl-3-trifluoromethylpyrazole synthesized in Reference Example 2 was dissolved in 35.0 g (0.15 mole) of a 24% aqueous potassium hydroxide solution. To the solution being stirred at room temperature was dropwise added 9.7 g (0.12 mole) of a 37% formalin solution, followed by stirring at the same temperature for 1 hour. Then, there were added 70.0 g (0.3 mole) of a 24% aqueous potassium hydroxide solution and 100 ml of acetonitrile. Therein was blown 17.3 g (0.20 mole) of chlorodifluoromethane at room temperature in 2 hours, followed by stirring at room temperature for 2 hours to give rise to a reaction. After the reaction, the organic layer which appeared by phase separation, was concentrated under reduced pressure to obtain 28.0 g (purity: 93.6%, yield: 84.9%) of a crude solution of title compound. The crude solution was purified by silica gel column chromatography (n-hexane:ethyl acetate=5:1) to obtain a title compound as white crystals.

Provenance & Evidence