Synthesis
Carbon tetrabromide (0.075 mmol), AQN-2-CO2H (0.03 mmol) and anhydrous ethanol (5 mL) were added to a Pyrex test tube using 1,3,5-trimethoxybenzene (1a, 0.3 mmol) as the raw material. The reaction mixture was irradiated and stirred in air for 20 h at room temperature using a 21 W fluorescent lamp. Upon completion of the reaction, the mixture was concentrated in vacuum, quenched with sodium thiosulfate (Na2S2O3) solution and extracted with ethyl acetate (EtOAc). The organic layers were combined and dried with anhydrous magnesium sulfate (MgSO4), followed by vacuum concentration to remove the solvent. Purification of the residue by rapid chromatography on silica gel (eluent ratio hexane/ethyl acetate = 6:1) afforded the target product 2-bromo-1,3,5-trimethoxybenzene (2a) (66.8 mg, 90% yield) as a white solid.
References
[1] Synthetic Communications, 2007, vol. 37, # 2, p. 323 - 328
[2] Journal of Organic Chemistry, 2013, vol. 78, # 20, p. 10360 - 10368
[3] Bulletin of the Chemical Society of Japan, 1989, vol. 62, # 2, p. 591 - 593
[4] Canadian Journal of Chemistry, 2009, vol. 87, # 2, p. 440 - 447
[5] Tetrahedron Letters, 1997, vol. 38, # 25, p. 4415 - 4416
