反应详情

To a solution of 2-(2-amino-5-bromophenyl)propan-2-ol (27 g, 125 mmol) in anhydrous toluene was added at ambient temperature under a blanket of nitrogen acetylaldehyde (10.5 mL, 187 mmol). After 10 minutes, the mixture was passed through a pad of silica gel and filtrate was concentrated to yield 6-bromo-2,4,4-trimethyl-1,4-dihydro-2H-3,1-benzoxazine as off-white solid (25 g, 78%): 1H-NMR (DMSO-d6) δ 7.22 (d, 1H, J=2.2 Hz), 7.08 (dd, 1H, J=8.6, 2.3 Hz), 6.51 (d, 1H, J=8.6 Hz), 6.36 (s, 1H), 4.72 (m, 1H), 1.45 (s, 3H), 1.40 (s, 3H), 1.25 (d, 3H, J=5.5 Hz).

1. concentrationwas concentrated