6-BroMo-7-fluoro-2,4-dihydro-1,4-benzoxazin-3-one synthesis

Yield:355423-58-4 44%

Reaction Conditions:

with N-Bromosuccinimide in acetonitrile at 20; for 5 h;

Steps:

7

INTERMEDIATE 76-Bromo-7-fluoro-4H-benzori.4]oxazin-3-oneTo a solution of Intermediate 6 (4.1 g, 25.0 mmol) in MeCN (120 mL) was added NBS (5.41 g, 30 mmol). The reaction mixture was stirred for 4 h at r.t. before addition of further NBS (0.45 g, 2.5 mmol) and MeCN (30 mL) and stirring for a further 1 h. It was then concentrated in vacuo. The resulting residue was slurried in water (10O mL). The solid material was filtered off, washed with water and dried in vacuo to give the title compound (2.7 g, 44%) as an off-white solid. δ_η (DMSO-d₆) 10.81 (IH, s), 7.12 (IH, d, J 9.4 Hz), 7.09 (IH, d, J 7.0 Hz), 4.63 (2H, s).

References:

WO2009/71895,2009,A1 Location in patent:Page/Page column 96