反应详情

To a solution of ethyl 1-(2-chloro-5-fluoropyrimidin-4-yl)-3-methyl-1H-pyrazole-4-carboxylate 1 (4.9 g, 17.2 mmol) in 60 mL of anhydrous tetrahydrofuran (THF), was slowly added 38 mL (38 mmol) of 1M solution of di-isobutylaluminum hydride (DIBAL) in toluene with ice bath cooling. After being stirred for 2 hours at the same temperature, the reaction was quenched by slow addition of 1N-NaOH solution. It was diluted with ethyl acetate and washed with brine. The collected organic layer was dried over anhydrous sodium sulfate and then partially concentrated in vacou. To this, n-hexanes were added to form pale yellow precipitates. The resulting solids were collected by filtration and rinsed with n-hexanes and then dried with high vacuum to give 3.7 g (90%) of Intermediate No. 2; 1H NMR (300 MHz, CDCl3) δ 8.57 (1H, d, J=3.3 Hz), 8.52 (1H, s), 7.94 (1H, s), 4.72 (2H, s); MS (ESI) m/z 243 [M+H]+.

1. temperaturecooling
2. customthe reaction was quenched by slow addition of 1N-NaOH solution
3. additionIt was diluted with ethyl acetate
4. washwashed with brine
5. dry with materialThe collected organic layer was dried over anhydrous sodium sulfate
6. concentrationpartially concentrated in vacou
7. additionTo this, n-hexanes were added
8. customto form pale yellow precipitates
9. filtrationThe resulting solids were collected by filtration
10. washrinsed with n-hexanes
11. customdried with high vacuum