Sodium hydride → 2-(2-Bromopyridin-3-yl)acetaldehyde

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Reaction Steps

To a white suspension of sodium hydride (1.36 g, 34 mmol) in DMSO (16 mL) at room temperature was added clear solution of (methoxymethyl)triphenyl)phosphonium chloride in DMSO (40 mL). The mixture became a yellow suspension. To the above suspension was added 2-bromonicotinaldehyde (2.48 g, 13.3 mmol) in DMSO (16 mL) dropwise. The mixture was stirred at room temperature for 20 hours then treated with excess sodium bicarbonate (sat), extracted with ether. The combined ether layer was washed with brine, dried over magnesium sulfate and concentrated. Purification by chromatography on silica gel gave E and Z mixture of 2-bromo-3-(2-methoxyvinyl)pyridine (1.88 g, 66%) as yellow oil. A solution of E and Z mixture of 2-bromo-3-(2-methoxyvinyl)pyridine(1.88 g, 8.79 mmol) in formic acid (96%, 10 mL) was stirred at 60° C. for 16 hours and at 80° C. for 3 hours before cooled to room temperature. Most of formic acid was removed. The mixture was diluted with ethyl acetate, washed with sodium bicarbonate and brine, dried over magnesium sulfate and concentrated. Purification by chromatography on silica gel gave 2-(2-bromopyridin-3-yl)acetaldehyde (864 mg, 53% yield) as yellow solid.

Provenance & Evidence