43192-34-3

The general procedure for the synthesis of 4-bromo-3-methoxybenzaldehyde from 3-methoxy-4-bromobenzonitrile was as follows: to a solution of 4-bromo-3-methoxybenzonitrile (0.38 g, 1.8 mmol) in toluene (25 mL) at -78 °C was slowly added DIBAL-H (1.0 M solution of THF, 3.6 mmol). The reaction temperature was maintained at -78 °C and stirred for 30 min, then gradually warmed to room temperature and continued stirring for 5 h. The reaction was completed by the addition of methanol (1.0 M THF solution). Upon completion of the reaction, methanol (15 mL) was added to quench the reaction and stirring was continued for 30 minutes. Subsequently, 10% aqueous sulfuric acid (10 mL) was added for acidification and extracted with ethyl acetate. The organic layers were combined, dried by adding anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (eluent: hexane/ether=4:1) to afford 4-bromo-3-methoxybenzaldehyde in white powder form in 41% yield.

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[2] Organic and Biomolecular Chemistry, 2015, vol. 13, # 37, p. 9564 - 9569
[3] Patent: KR2017/17173, 2017, A. Location in patent: Paragraph 0078