Intermediate Preparation: methyl 6-bromo-1H-indole-3-carboxylate; (Trimethylsilyl)diazomethane (2.0 M hexane solution, ca. 9 mL) was added dropwise to a solution of 6-bromo-1H-indole-3-carboxylic acid (960 mg, 4.00 mmol) in methanol (9.5 mL) at room temperature, with the dropwise addition time being controlled to be within 2 minutes. After the reaction mixture took on a yellow color, it was concentrated under reduced pressure. The concentrated residue was redissolved in methanol and concentrated again under reduced pressure. This dissolution-concentration process was repeated several times to give the title compound methyl 6-bromo-1H-indole-3-carboxylate as a solid product in 100% yield.ES/MS m/e: 256.0 (M+2).
