반응 #8587

반응 방정식

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

수율 77.0%

용매

toluene

반응 조건

후처리

1. 1
   온도to reflux for 3.5 hours
2. 2
   기타quenched by the dropwise addition of aqueous sodium bicarbonate
3. 3
   workup.ADDITIONEther was added
4. 4
   세척the organic layer was washed with brine
5. 5
   추출The aqueous layer was extracted with ether
6. 6
   건조the-combined organics were dried over magnesium sulfate
7. 7
   여과filtered
8. 8
   농축concentrated
9. 9
   기타The residue was purified by recrystallization from ethyl acetate-hexanes

실험 절차

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).

출처