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温度

0 °C

A solution of 318 mg (1.48 mmol) of 2-(4-aminophenyl)-ethanesulfonic acid methylamide (as prepared in the previous step) in CH2Cl2 (20 mL) was cooled to 0° C. and treated with 251 mg (1.41 mmol) of NBS at that temperature for 1 h. The mixture was diluted with CH2Cl2 (30 mL) and washed with saturated aqueous NaHCO3 (1×30 mL). The organic layer was dried (MgSO4) and concentrated in vacuo. Silica gel chromatography of the residue on a 25-g Varian MegaBond Elut SPE column with 50% EtOAc-hexane afforded 354 mg (81%) of the title compound as a white solid: 1H-NMR (CD3CN; 400 MHz): δ 7.34 (d, 1H, J=2.0 Hz), 7.03 (dd, 1H, J=8.0, 2.0 Hz), 6.77 (d, 1H, J=8.0 Hz), 5.06-4.97 (m, 1H), 4.48-4.40 (br s, 2H), 3.25-3.18 (m, 2H), 2.93-2.86 (m, 2H), 2.67 (d, 3H, J=5.2 Hz). Mass spectrum (ESI, m/z): Calcd. for C9H13N2O2SBr, 293.0/295.0 (M+H). found 293.0/295.0.

1. washwashed with saturated aqueous NaHCO3 (1×30 mL)
2. dry with materialThe organic layer was dried (MgSO4)
3. concentrationconcentrated in vacuo