反应详情

A 0° C. solution of H2SO4 (11 mL) was slowly treated with H2O2 (30%, 5.5 mL), in an open flask, stirred for 5 min, treated drop-wise with a solution of 5-bromo-6-ethylpyridin-2-amine (3.79 g, 18.85 mmol) in H2SO4 (10 mL) warmed to RT as the cooling bath expired and stirred overnight. The solution was poured into ice water (200 mL), treated with DCM, cooled to 0° C. and treated slowly with 50% NaOH until pH=10. The layers were separated, the aqueous layer extracted with additional DCM (1×) and the combined organics were washed with brine, dried over Na2SO4 and concentrated to dryness to afford crude 3-bromo-2-ethyl-6-nitropyridine (3.168 g, 71%) which was used without further purification. 1H NMR (400 MHz, DMSO-d6): δ 8.44 (d, J=8.5 Hz, 1 H), 8.05 (d, J=8.5 Hz, 1 H), 2.97 (q, J=7.5 Hz, 2 H), 1.24 (t, J=7.5 Hz, 3 H); MS (ESI) m/z: 231.0 (M+H+).

1. stirringstirred overnight
2. temperaturecooled to 0° C.
3. customThe layers were separated
4. extractionthe aqueous layer extracted with additional DCM (1×)
5. washthe combined organics were washed with brine
6. dry with materialdried over Na2SO4
7. concentrationconcentrated to dryness