3,5-Dimethylpyrazole → HCID 12926677、化合物

A suspension of 3,5-dimethylpyrazole (3.9 g, 40.7 mmol) and sodium hydride (60% in mineral oil, 1.7 g) in dichloromethane (50 mL) was added dropwise to a cooled (−78° C.) solution of 4,6-dichloro-2-methanesulfonyl-pyrimidine (10 g, 38.7 mmol) in dichloromethane (200 mL). The mixture was stirred at −78° C. for one hour. The reaction was carefully quenched at the same temperature by addition of water (150 mL). The mixture was allowed to warm to room-temperature. Brine (150 mL) was added and the phases were separated. The aqueous phase was extracted with dichloromethane (4×200 mL). The combined organic layers were washed with brine, dried over sodium sulphate, filtrated and concentrated in vacuo. The crude product was purified by flash chromatography (ethyl acetate/heptane as eluent) to give 4,6-dichloro-2-(3,5-dimethyl-pyrazol-1-yl)-pyrimidine (5.5 g, 59%) as a white crystalline compound.