Formaldehyde → HCID 66718894, compound

Participants

Reaction Steps

In 100 ml of DMF were suspended 16.6 g (0.10 mole) of the 5-hydroxy-1-methyl-3-trifluoromethylpyrazole synthesized in Reference Example 1 and 20.9 g (0.15 mole) of potassium carbonate. In this suspension being stirred at room temperature was placed 4.5 g (0.15 mole) of paraformaldehyde, followed by stirring at the same temperature for 1 hour. Then, 41.8 g (0.30 mole) of potassium carbonate was added. Thereto was dropwise added 44.7 g (0.30 mole) of cyclopentyl bromide. The reaction mixture was heated to 60° C., followed by stirring for 12 hours to give rise to a reaction. After the reaction, 200 ml of ethyl acetate and 200 ml of water were added. The organic layer, which appeared by phase separation, was separated. The aqueous layer was subjected to re-extraction with 50 ml of ethyl acetate. The two organic layers were combined and washed with 50 ml of water, 30 ml of a saturated aqueous ammonium chloride solution and 30 ml of a saturated aqueous sodium chloride solution in this order. The resulting organic layer was dried over anhydrous sodium sulfate and then concentrated under reduced pressure to obtain 41.9 g (purity: 42.2%, yield: 67.0%) of a crude solution of title compound. The crude solution was subjected to vacuum distillation to obtain a title compound as a light yellow transparent solution.

Provenance & Evidence