Carbon tetrabromide → 4-(Bromomethyl)-2-chloropyridine

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Reaction Steps

Triphenylphosphine (19 g, 71 mmol) and carbon tetrabromide (29 g, 88 mmol) were added to a solution of 2-chloropyridine-4-methanol (8.5 g, 59 mmol, Reference compound No. 7-1) in methylene chloride (250 mL), then the mixture was stirred at room temperature for 1 hour. The solvent was evaporated under reduced pressure, and then the resulting residue was purified by silica gel column chromatography to give 4-bromomethyl-2-chloropyridine. Immediately, 2-mercaptonicotinic acid (9.1 g, 59 mmol) was added to a solution of this bromo intermediate in N,N-dimethylformamide (100 mL) under ice-cooling, then triethylamine (25 mL, 180 mmol) was added dropwise thereto. The reaction mixture was stirred at room temperature for 15 hours, then diethyl ether (100 mL) and water (600 mL) were added thereto, and the organic layer and the aqueous layer were separated. The aqueous layer was adjusted to pH 6 with 2N hydrochloric acid, the precipitated solid was filtered off. The solid was washed with water and diethyl ether, and dried at 50° C. under reduced pressure to give 12 g of the title reference compound as a yellow solid. (Yield 73%)

Provenance & Evidence