Dimethylformamide → 5-Chloro-2-(4-fluorophenyl)pyrazolo[1,5-a]pyridine-3-carbaldehyde

Participants

Reaction Steps

Phosphorous oxychloride (0.6 mL, 6.4 mmol) was added to N,N-dimethylformamide (10 mL) and the resulting mixture stirred at room temperature for 10 minutes. 5-Chloro-2-(4-fluorophenyl)pyrazolo[1,5-α]pyridine (1.0 g, 4.1 mmol) was added and the reaction mixture was stirred at room temperature for 12 hours. The reaction mixture was poured into ice-water and neutralized to pH 7 with aquous ammonium hydroxide. The resulting slurry was extracted with dichloromethane (3×40 mL). The combined organics were washed with brine, dried (magnesium sulfate), filtered and concentrated to give, after recrystallization from acetonitrile, 5-chloro-2-(4-fluorophenyl)pyrazolo [1,5-α]pyridine-3-carbaldehyde (0.95 g, 85%) as a white solid. 1H-NMR (CDCl3): δ10.07 (s, 1H), 8.49 (d, 1H), 8.44 (d, 1H), 7.78 (q, 2H), 7.22 (t, 2H), 7.07 (dd, 1H); MS m/z 275 (M+1).

Provenance & Evidence