2,6-Dibromo-3-methoxy-5-nitropyridine → 5,7-Dibromo-4-methoxy-6-azaindole

Participants

Reaction Conditions

Reaction Steps

Vinylmagnesium bromide (0.85 M in THF, 97.7 mL, 83.0 mmol) was added over 30 min. to a stirring solution of 2,6-dibromo-3-methoxy-5-nitropyridine (7.4 g, 23.7 mmol) in THF (160 mL) at −75° C. The solution was stirred 1 h at −75° C., overnight at −20° C., recooled to −75° C. and quenched with saturated aqueous NH4Cl (˜100 mL). The reaction mixture was allowed to warm to rt, washed with brine (˜100 mL) and extracted with Et2O (150 mL) and CH2Cl2 (2×100 mL). The combined organics were dried (MgSO4), filtered and concentrated. The residue was purified by flash column chromatography (SiO2, 3:1 hexanes/EtOAc) to yield 5,7-dibromo-4-methoxy-6-azaindole 36 (1.10 g, 3.60 mmol, 15%) as a pale yellow solid.

Provenance & Evidence