反应详情

To a solution of 2-(6-bromo-3-thioxo-2,3-dihydro-benzo[1,4]oxazin-4-yl)-propionic acid ethyl ester (28 g, 81.4 mmol) in EtOH (100 mL) was added hydrazine hydrate (98%, 13.1 g, 162.8 mmol). The reaction mixture was stirred at ambient temperature overnight. The precipitate was collected by filtration and washed with cold EtOH (3×10 mL) to give 6-bromo-4-methyl-2,10-dihydro-9-oxa-1,2,4a-triaza-phenanthren-3-one as a yellow solid (22.0 g, 74.3 mmol, 92%). 1H NMR (DMSO-d6, 400 MHz): δ 10.83 (s, 1H), 7.41 (d, J=2.0 Hz, 1H), 7.11 (d, J=2.0 Hz, J=8.4 Hz, 1H), 6.94 (d, J=8.4 Hz, 1H), 4.82 (q, J=6.8 Hz, 1H), 4.62 (d, J=13.2 Hz, 2H), 1.28 (d, J=6.8 Hz, 3H).

1. filtrationThe precipitate was collected by filtration
2. washwashed with cold EtOH (3×10 mL)