反应详情

温度

0 °C

Dissolve 3-trifluoromethyl-1H-pyrazole-4-carboxylic acid ethyl ester (2.0 g, 9.61 mmol) in N,N-dimethylformamide (20 mL) and cool to 0° C. Add sodium hydride (0.58 g, 14.42 mmol, 60% dispersion in oil) and stir at 0° C. for 20 min. Add iodomethane (0.90 mL, 14.42 mmol) and allow to warm to room temperature over 18 hr. Partition between ethyl acetate (100 mL) and water (50 mL). Separate the organic layer and wash with water (5×50 mL) and saturated aqueous sodium chloride solution (50 mL). Dry (sodium sulfate), filter, concentrate and purify (silica gel chromatography, eluting with 90:10 hexanes:ethyl acetate), to give 1-methyl-3-trifluoromethyl-1H-pyrazole-4-carboxylic acid ethyl ester (1.74 g, 81.7%). 1H-NMR (400 MHz, CDCl3) δ 7.92 (s, 1H), 4.27 (q, 2H), 3.95 (s, 3H), 1.33 (t, 3H).

1. temperatureto warm to room temperature over 18 hr
2. customPartition between ethyl acetate (100 mL) and water (50 mL)
3. customSeparate the organic layer
4. washwash with water (5×50 mL) and saturated aqueous sodium chloride solution (50 mL)
5. dry with materialDry (sodium sulfate)
6. filtrationfilter
7. concentrationconcentrate
8. custompurify
9. wash(silica gel chromatography, eluting with 90:10 hexanes:ethyl acetate)