tert-Butyl 3-bromo-1H-pyrrolo[2,3-b]pyridine-1-carboxylate

Synthesis

Under nitrogen atmosphere, 3-bromo-1H-pyrrolo[2,3-b]pyridine (0.10 g, 0.50 mmol) was dissolved in tetrahydrofuran (THF, 4.0 mL) followed by the addition of 4-dimethylaminopyridine (DMAP, 0.006 g, 0.06 mmol). The reaction mixture was cooled to -20 °C and di-tert-butyl dicarbonate (Boc anhydride, 122 μL, 0.56 mmol) was slowly added. The reaction mixture was gradually warmed to room temperature and stirred continuously for 2 hours. The reaction progress was monitored by thin layer chromatography (TLC). Upon completion of the reaction, water (20 mL) was added to the mixture and extracted with ethyl acetate (EtOAc, 3 × 50 mL). The organic phases were combined, dried with anhydrous sodium sulfate (Na2SO4), filtered and concentrated. The crude product was purified by silica gel column chromatography (60-120 mesh, 5% ethyl acetate-hexane as eluent) to afford the target product 1-BOC-3-bromo-7-azaindole as an oil (0.12 g, 79% yield).

References

[1] Synthesis, 1999, # 4, p. 615 - 620
[2] Patent: WO2009/74812, 2009, A1. Location in patent: Page/Page column 59