反应详情

To a solution of di-tert-butyl [5-(5-chloro-2-hydroxyphenyl)-1,2-benzoxazol-3-yl]imidodicarbonate (2.00 g, 4.34 mmol) in acetonitrile (45 mL) was added N-bromosuccinimide (0.811 g, 4.56 mmol). The mixture was stirred at ambient temperature for 0.5 h and concentrated in vacuo. The residue was purified by column chromatography eluting with a 5-15% gradient of ethyl acetate in hexanes) to afford di-tert-butyl [5-(3-bromo-5-chloro-2-hydroxyphenyl)-1,2-benzoxazol-3-yl]imidodicarbonate as an orange solid in 35% yield (0.83 g): 1H NMR (300 MHz, DMSO-d6) δ 9.55 (s, 1H), 7.95-7.93 (m, 1H), 7.89-7.86 (m, 2H), 7.69 (d, J=2.6 Hz, 1H), 7.38 (d, J=2.6 Hz, 1H), 1.39 (s, 18H); MS (ES−) m/z 536.9 (M−1), 538.9 (M−1), 540.9 (M−1).

1. concentrationconcentrated in vacuo
2. customThe residue was purified by column chromatography
3. washeluting with a 5-15% gradient of ethyl acetate in hexanes)