5-Bromo-3-pyridinecarboxaldehyde → 1255957-49-3

Participants

Reaction Conditions

Reaction Steps

To a solution of methyltriphenylphosphonium bromide (2.97 g, 8.33 mmol) in THF (45 ml) at −78° C. was added n-butyllithium (2.5 M in hexanes, 2.7 mL, 6.75 mmol). The resulting yellow reaction mixture was stirred for 30 min at −78° C. In a separate flask THF (9 mL) was added to 5-bromonicotinaldehyde (CAS#113118-81-3, 837 mg, 4.5 mmol). The resulting 5-bromonicotinaldehyde solution was the transferred, via cannula, to the phosphonium ylide mixture followed by a 2 mL THF wash. The reaction was allowed to warm to room temperature over 120 minutes and then permitted to stir for an additional 30 minutes. The reaction was then quenched with saturated aqueous sodium bicarbonate and diluted with ethyl acetate. The layers were separated and the organic layer was washed with saturated aqueous sodium bicarbonate. The organic layer was concentrated to near dryness and the resulting residue was then diluted with ethyl acetate and 1M sodium bisulfate and the layers were separated. The organic layer was extracted two additional times with 1M sodium bisulfate. The aqueous layers were combined, diluted with dichloromethane, and neutralized via the careful addition of saturated aqueous sodium bicarbonate and solid sodium carbonate. The layers were separated and the now basic aqueous layer was extracted three additional times with dichloromethane. The dichloromethane layers were combined, dried over anhydrous sodium sulfate, filtered and concentrated. The resulting residue was purified by silica gel flash chromatography (ethyl acetate-dichloromethane, 0 to 16%) to furnish 3-bromo-4-vinyl-pyridine; MS: (ES+) m/z 183.9 (M+H)+

Provenance & Evidence