[NH2:1][C:2]1[CH:7]=[CH:6][C:5]([CH:8]([CH3:16])[C:9]([O:11][C:12]([CH3:15])([CH3:14])[CH3:13])=[O:10])=[CH:4][CH:3]=1.[Br:17]N1C(=O)CCC1=O.O>CN(C=O)C>[NH2:1][C:2]1[CH:3]=[CH:4][C:5]([CH:8]([CH3:16])[C:9]([O:11][C:12]([CH3:15])([CH3:14])[CH3:13])=[O:10])=[CH:6][C:7]=1[Br:17]To a solution of tert-butyl 2-(4-aminophenyl)propanoate (5.00 g, 22.6 mmol) in DMF (15 mL) was added a solution of N-bromosuccinimide (4.22 g, 23.7 mmol) in DMF (15 ML) at room temperature which was maintained by water bath. The mixture was stirred overnight, poured into water and extracted with ethyl acetate. The organic layer was separated, washed with water, then brine, dried over sodium sulfate, and filtered. After concentration, the residue was purified by flash chromatography (9:1 hexanes/ethyl acetate) to give tert-butyl 2-(4-amino-3-bromophenyl)propanoate (6.00 g, 85%) as a brown oil: 1H NMR (500 MHz, CDCl3) δ 7.34 (d, J=1.6 Hz, 1H), 7.04 (dd, J=8.1, 1.7 Hz, 1H), 6.71 (d, J=8.2 Hz, 1H), 4.01 (br s, 2H), 3.46 (q, J=7.1 Hz, 1H), 1.39 (m, 12H).
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