N-methyl-2-pyrrolidone → Potassium Hydroxide

Participants

Reaction Steps

To a 1 L flask is charged 3,5-dibromopyridine-4-carboxaldehyde (50.0 g, 189 mmol, 1.0 eq) and 4-fluorophenylhydrazine hydrochloride (31.0 g, 191 mmol, 1.01 eq). NMP (250 mL) is charged, and the resulting slurry is stirred at ambient temperature for 2 hours. A solution of aqueous KOH is prepared from 85% KOH pellets (27.4 g, 415 mmol, 2.2 eq) and water (27.4 mL), and this KOH solution is charged to the reaction mixture. The batch is heated to 80° C. and is held at this temperature for 30-60 minutes. Water (250 mL) is then charged at 80° C., and the resulting slurry is cooled to ambient temperature over 4-16 hours. The slurry is filtered, the solid is washed with water, and oven dried under vacuum to afford 4-bromo-1-(4-fluorophenyl)-1H-pyrazolo[3,4-c]pyridine as a solid.

Provenance & Evidence