反应详情

Potassium bis(trimethylsilyl)amide (20% toluene solution, 3.05 g) was added to a mixture of bis(2,2,2-trifluoroethyl) (methoxycarbonylmethyl)phosphonate (973 mg), 18-crown-6 (4.04 g) and tetrahydrofuran (50 mL) at −78° C. Furthermore, 5-(4-fluorophenyl)-1-methyl-1H-pyrazole-4-carbaldehyde (312 mg) was added and the mixture was stirred overnight while allowing to warm from −78° C. to room temperature. Saturated aqueous ammonium chloride was added to the reaction mixture and the mixture was extracted with ethyl acetate. The organic layer was washed successively with 1N hydrochloric acid, water and saturated brine, dried over anhydrous magnesium sulfate, and concentrated. The residue was subjected to silica gel column chromatography to give methyl (2Z)-3-[5-(4-fluorophenyl)-1-methyl-1H-pyrazol-4-yl]acrylate as crystals (0.35 g, yield 95%) from a fraction eluted with hexane-ethyl acetate (4:1-1:1, v/v) (recrystallized from ethyl acetate-hexane). melting point: 108-109° C.

1. temperatureto warm from −78° C. to room temperature
2. extractionthe mixture was extracted with ethyl acetate
3. washThe organic layer was washed successively with 1N hydrochloric acid, water and saturated brine
4. dry with materialdried over anhydrous magnesium sulfate
5. concentrationconcentrated