反应详情

NaOAc (3.78 g, 46.2 mmol) in H2O (30 mL) was added to a soln of 7-bromo 4-chromanone (3.5 g, 15.4 mmol) and hydroxyl-amine hydrochloride (1.75 g, 23.1 mmol) in EtOH (70 ml). The reaction was heated at reflux for 2 h, cooled to room temperature, and concentrated. The residue was diluted with H2O and a precipitate was filtered to give 7-bromochroman-4-one oxime obtained as the needle like crystals 3.5 g (98%). LCMS 244 (M+2H) RT=1.7 min (Condition 2); 1H NMR (DMSO-d6) 11.37 (s, OH, 1H), 7.76-7.70 (d, 1H), 7.09-7.13 (d, 2H), 4.16-4.20 (t, 2H), 2.79-2.83 (t, 2H).

1. temperatureThe reaction was heated
2. temperatureat reflux for 2 h
3. concentrationconcentrated
4. additionThe residue was diluted with H2O
5. filtrationa precipitate was filtered