反应详情

To a solution of 2-(6-bromo-7-methyl-3-thioxo-2,3-dihydro-benzo[1,4]oxazin-4-yl)-propionic acid ethyl ester (0.192 g, 0.536 mmol) in EtOH (3 mL) was added anhydrous hydrazine hydrate (0.107 g, 2.144 mmol) and the mixture was heated at reflux for 4 h. The reaction mixture was cooled to ambient temperature and evaporated in vacuo. The residue was purified by column chromatography on silica gel (eluting with 25% EtOAc in petroleum ether) to give 6-bromo-4,7-dimethyl-2,10-dihydro-9-oxa-1,2,4a-triaza-phenanthren-3-one as white solid (0.15 g, 90%). 1H NMR (DMSO-d6, 400 MHz): δ 10.80 (s, 1H), 7.46 (s, 1H), 7.02 (s, 1H), 4.86 (q, J=6.8 Hz, 1H), 4.60 (dd, J=12.8 Hz, 2H), 2.26 (s, 3H), 1.27 (d, J=6.8 Hz, 3H).

1. temperaturethe mixture was heated
2. temperatureat reflux for 4 h
3. customevaporated in vacuo
4. customThe residue was purified by column chromatography on silica gel (eluting with 25% EtOAc in petroleum ether)