Réaction #8596

Équation de réaction

Boron trifluoride

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

acetic anhydride

→

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

Rendement 65.2%

Solvants

toluene

Conditions de réaction

Traitement

1. 1
   Températurethe resulting solution was heated
2. 2
   Températureat reflux for 4 hours
3. 3
   Autrequenched by the dropwise addition of saturated aqueous sodium bicarbonate
4. 4
   ExtractionThe reaction was extracted with ethyl acetate
5. 5
   Lavagethe ethyl acetate phase washed with brine
6. 6
   Séchagedried (magnesium sulfate)
7. 7
   Filtrationfiltered
8. 8
   Concentrationconcentrated
9. 9
   AutreThe residue was purified by recrystallization from ethyl acetate-hexanes

Mode opératoire

To a solution of 7-chloro-2-(4-methoxyphenyl)pyrazolo[1,5-α]pyridine (18.7 g, 72.4 mmol) in toluene (300 mL) at room temperature was added acetic anhydride (8.2 mL, 86.9 mmol). Boron trifluoride diethyletherate (10.1 mL, 79.6 mmol) was then added dropwise and the resulting solution was heated at reflux for 4 hours. The reaction mixture was cooled to room temperature and quenched by the dropwise addition of saturated aqueous sodium bicarbonate. The reaction was extracted with ethyl acetate, and the ethyl acetate phase washed with brine, dried (magnesium sulfate), filtered and concentrated. The residue was purified by recrystallization from ethyl acetate-hexanes to give 1-[7-(chloro)-2-(4-methoxyphenyl)pyrazolo[1,5-α]pyridin-3-yl]ethanone (14.2 g, 65%) as reddish needles.1H NMR (CDCl3): δ 8.37 (dd, 1H), 7.49 (dd, 2H), 7.39 (dd, 1H), 7.10 (dd, 1H), 6.98 (dd, 2H), 3.84 (s, 3H), 2.13 (s, 3H); MS m/z 301 (M+1).

Source