Synthesis
(1) Synthesis of 3-methoxy-4-nitrobenzaldehyde: 3-hydroxy-4-nitrobenzaldehyde (500 mg, 2.99 mmol) and potassium carbonate (0.42 g, 3.0 mmol) were dissolved in 6.0 mL of N,N-dimethylformamide. Iodomethane (0.38 mL, 6.0 mmol) was slowly added to the reaction system at room temperature, followed by continuous stirring at the same temperature for 5 hours. After completion of the reaction, the reaction mixture was diluted with ethyl acetate and water and separated. The organic layer was washed twice with saturated brine and subsequently dried with anhydrous magnesium sulfate. After filtration, the filtrate was concentrated under reduced pressure and the residue was purified by silica gel column chromatography (eluent: hexane/ethyl acetate = 4/1 to 1/1) to afford the target compound, 3-methoxy-4-nitrobenzaldehyde, as a light yellow powder (518 mg, 96% yield).
References
[1] ACS Medicinal Chemistry Letters, 2017, vol. 8, # 10, p. 1002 - 1006
[2] Patent: WO2016/124747, 2016, A1. Location in patent: Page/Page column 62; 63
[3] Patent: US2018/202388, 2018, A1
[4] Patent: EP2123637, 2009, A1. Location in patent: Page/Page column 19
[5] Organic and Biomolecular Chemistry, 2014, vol. 12, # 30, p. 5629 - 5633
