反应详情

A 0° C. solution of H2SO4 (11 mL, 10.83 mmol) was treated slowly with 30% hydrogen peroxide (5.5 mL, 9.42 mmol) in an open flask, stirred for 5 minutes, treated drop-wise with a solution of 5-bromo-6-ethylpyridin-2-amine (3.83 g, 19.05 mmol) in H2SO4 (11 mL) and stirred overnight as the cooling bath expired. The solution was poured into ice water, treated with DCM, cooled in an ice bath and treated slowly with 50% NaOH until pH˜9. The layers were separated, the aqueous layer extracted with DCM (1×) and the combined organics were washed with brine, dried over Na2SO4, concentrated to dryness and purified via silica gel chromatography (EtOAc/Hex) to afford 3-bromo-2-ethyl-6-nitropyridine (2.31 g, 52%) as a yellow oil. 1H NMR (400 MHz, DMSO-d6): δ 8.43 (d, J=8.5 Hz, 1H), 8.04-8.03 (m, 1H), 2.96 (q, J=7.5 Hz, 2H), 1.24 (t, J=7.5 Hz, 3H); MS (ESI) m/z: 233.0 (M+H+).

1. stirringstirred overnight as the cooling bath
2. temperaturecooled in an ice bath
3. customThe layers were separated
4. extractionthe aqueous layer extracted with DCM (1×)
5. washthe combined organics were washed with brine
6. dry with materialdried over Na2SO4
7. concentrationconcentrated to dryness
8. custompurified via silica gel chromatography (EtOAc/Hex)