Potassium Carbonate → 2-(3-Bromo-1H-pyrazol-1-yl)-3-chloropyridine

Participants

Reaction Conditions

Reaction Steps

To a mixture of 2,3-dichloropyridine (27.4 g, 185 mmol) and 3-bromopyrazole (i.e. the product of Step B) (25.4 g, 176 mmol) in dry N,N-dimethylformamide (88 mL) was added potassium carbonate (48.6 g, 352 mmol), and the reaction mixture was heated to 125° C. for 18 hours. The reaction mixture was cooled to room temperature and poured into ice water (800 mL). A precipitate formed. The precipitated solids were stirred for 1.5 hrs, filtered and washed with water (2×100 mL). The solid fiber cake was taken up in methylene chloride and washed separately with water, 1 N hydrochloric acid, saturated aqueous sodium bicarbonate solution, and brine. The organic extracts were then dried over magnesium sulfate and concentrated to afford 39.9 g of a pink sold. The crude solid was suspended in hexane and stirred vigorously for 1 hr. The solids were filtered, washed with hexane and dried to afford the title product as an off-white powder (30.4 g) determined to be >94% pure by NMR. This material was used without further purification in Step D.

Provenance & Evidence