1035229-33-4

1035229-32-3

1035229-33-4

The general procedure for the synthesis of 5-(benzyloxy)-8-(2-chloroacetyl)-2H-benzo[b][1,4]oxazin-3(4H)-one using 8-acetyl-5-(benzyloxy)-2H-benzo[b][1,4]oxazin-3(4H)-one as a starting material was as follows: under stirring conditions, aqueous solution was added to 8-acetyl-5-(benzyloxy)-2H-benzo[b][1,4 ]oxazin-3(4H)-one (5.50 g, 18.5 mmol) to a mixed solution of dichloromethane (100 mL), acetic acid (33 mL) and water (5.5 mL) was added benzyltrimethylammonium dichloroiodate (14.2 g, 40.8 mmol). The reaction mixture was stirred at 65 °C for 20 hours. After completion of the reaction, the mixture was cooled to room temperature and treated with aqueous sodium bisulfate (5.78 g dissolved in 100 mL of water) and continued to stir for 30 minutes. The reaction mixture was diluted with ether (200 mL), and the resulting solid product was collected by filtration, washed sequentially with water and ether, and finally dried under vacuum at 40 °C to afford the target compound 5-(benzyloxy)-8-(2-chloroacetyl)-2H-benzo[b][1,4]oxazin-3(4H)-one (5.60 g, 17.4 mmol, 94% yield) as a yellow solid. The mass spectrum (ESI+) showed the molecular ion peak m/z 332 [M+1]+.