反应详情

To a solution of 4-(tert-butoxycarbonyl)-3,4-dihydro-2H-pyrido[3,2-b]-1,4-oxazine (2.0 g, 8.46 mmole) in MeOH (40 mL) was added Br2 (0.53 mL, 10.2 mmole) dropwise at 0° C. After 1 hr the mixture was concentrated. The residue was taken up in 1:1 Et2O/hexanes and filtered. The filtrate was concentrated under reduced pressure to give the title compound (1.27 g, 48%) as an oil which solidified under vacuum: 1H NMR (400 MHz, CDCl3) δ 8.10 (s, 1H), 7.33 (s, 1H), 4.25 (m, 2H), 3.92 (m, 2H), 1.54 (s, 9H).

1. concentrationAfter 1 hr the mixture was concentrated
2. filtrationfiltered
3. concentrationThe filtrate was concentrated under reduced pressure