166104-19-4

Di-tert-butyl dicarbonate (524 mg, 2.4 mmol) and 5-nitro-1H-indole (325 mg, 2.0 mmol) were used as raw materials and stirred in dichloromethane (6 mL) for 5 min at 0 °C. Subsequently, a catalytic amount of 4-dimethylaminopyridine (3 mg, 0.025 mmol) was added and stirring was continued for 30 min at room temperature. Upon completion of the reaction, the reaction was quenched by the addition of water (2 mL) and extracted with dichloromethane (15 mL x 3). The organic phases were combined, washed sequentially with water (20 mL) and saturated brine (15 mL × 2) and dried over anhydrous sodium sulfate. The solvent was removed by distillation under reduced pressure to afford the gray solid product tert-butyl 5-nitro-1H-indole-1-carboxylate (526 mg, 100% yield), which could be used in the next reaction without further purification.

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