反応 #8587

反応方程式

Boron trifluoride

7-chloro-2-(4-fluorophenyl)pyrazolo[1,5-α]pyridine

acetic anhydride

→

1-[7-chloro-2-(4-fluorophenyl)pyrazolo[1,5-α]pyridin-3-yl]ethanone

収率 77.0%

溶媒

toluene

反応条件

後処理

1. 1
   温度to reflux for 3.5 hours
2. 2
   その他quenched by the dropwise addition of aqueous sodium bicarbonate
3. 3
   workup.ADDITIONEther was added
4. 4
   洗浄the organic layer was washed with brine
5. 5
   抽出The aqueous layer was extracted with ether
6. 6
   乾燥the-combined organics were dried over magnesium sulfate
7. 7
   ろ過filtered
8. 8
   濃縮concentrated
9. 9
   その他The residue was purified by recrystallization from ethyl acetate-hexanes

実験手順

To a solution of 7-chloro-2-(4-fluorophenyl)pyrazolo[1,5-α]pyridine (10.0 g, 40.5 mmol) in toluene (225 mL) at room temperature was added acetic anhydride (4.6 mL, 48.6 mmol). Boron trifluoride diethyletherate (5.6 mL, 44.6 mmol) was then added dropwise and the resultant solution was heated to reflux for 3.5 hours. The reaction mixture was cooled to room temperature and quenched by the dropwise addition of aqueous sodium bicarbonate. Ether was added and the organic layer was washed with brine. The aqueous layer was extracted with ether and the-combined organics were dried over magnesium sulfate, filtered and concentrated. The residue was purified by recrystallization from ethyl acetate-hexanes to give 1-[7-chloro-2-(4-fluorophenyl)pyrazolo[1,5-α]pyridin-3-yl]ethanone (9.0 g, 77%) as redish needles.1H NMR (CDCl3): δ 8.41 (d, 1 H), 7.59 (m, 2 H). 7.45 (dd,1 H), 7.26–7.13 (m 3 H), 2.15 (s, 3 H); 19F NMR (CDCl3) δ −112.06; MS m/z 289 (M+1).

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