Dimethylformamide → (αZ)-4-Bromo-α-[(dimethylamino)methylene]benzeneacetaldehyde

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Reaction Conditions

Reaction Steps

Phosphoryl chloride (55.0 mL, 590 mmol) was added dropwise to N,N-dimethylformamide (80.0 mL) at 0° C. The reaction mixture was stirred at 0° C. for an additional 30 min after which 4-bromophenylacetic acid (43.0 g, 200 mmol) was added portion wise. The resulting mixture was heated at 70° C. overnight. After cooling, the reaction mixture was added slowly to a mixture of ice and water with external cooling. Ice was added intermittently to keep the temperature <10° C. When the quenching was complete, potassium carbonate and ice were added slowly until pH 11 was achieved. Small quantities of ethanol were added to control frothing. To the alkaline mixture was added toluene (120 mL), and the reaction mixture was refluxed for 1.5 hours and cooled to ambient temperature. The aqueous layer was extracted with toluene (2×50 mL). The combined organic extracts were washed with water, dried over sodium sulfate, filtered, and concentrated under reduced pressure. The residue was recrystallized from dichloromethane/hexanes to give the desired product. (26.5 g, 52%) LCMS: (M+H)=281.0/283.0.

Provenance & Evidence