p-Aminoacetophenone → 1-(4-Amino-3-bromo-phenyl)-ethanone

Participants

Reaction Steps

1-(4-aminophenyl)ethanone (2.50 g; 18.5 mmol) was dissolved in 100 mL toluene. NBS (3.30 g; 18.8 mmol) was added portionwise. After 15 min stirring at RT, the organic phase was washed with water twice, and dried over Na2SO4. The solvent was removed by rotavap to get oil, which was purified by silica gel chromatography, to afford 1.7 g of a white solid, 1-(4-amino-3-bromophenyl)ethanone (1.7 g; 7.94 mmol). The intermediate was dissolved in CH2Cl2. The reaction mixture was cooled to 0° C. Trifluoroacetic anhydride (2.0 g; 9.52 mmol) and NEt3 (1.0 g; 9.90 mmol) were added sequentially. The reaction mixture was stirred at RT for another hour. The organic phase was washed twice with water, dried over MgSO4. The solvent was removed, to afford 2.4 g (yield 42%) of product as white solid. 1H NMR (400 MHz, CDCl3) δ 8.61 (s, 1H, N—H), 8.46, (d, 3JHH=8.6 Hz, 1H, Ar—H), 8.21 (d, 4JHH=2.0 Hz, 1H, Ar—H), 7.95 (dd, 3JHH=8.6 Hz, 4JHH=1.9 Hz, 1H, Ar—H), 2.58 (s, 3H, CH3).

Provenance & Evidence