反应详情

To a solution of di-tert-butyl (5-bromo-1,2-benzoxazol-3-yl)imidodicarbonate (3.9 g, 9.3 mmol) in dimethoxyethane (100 mL) was added (5-chloro-2-hydroxyphenyl)boronic acid (1.6 g, 9.3 mmol), tetrakis(triphenylphosphine)palladium (1.1 g, 0.9 mmol) and 2 M aqueous sodium carbonate (9.3 mL, 18.6 mmol). The mixture was heated at reflux for 5 h, allowed to cool to ambient temperature and concentrated in vacuo. The residue was diluted with ethyl acetate (75 mL), washed with water (2×40 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The residue was purified by column chromatography eluting with a 10-50% gradient of ethyl acetate in hexanes to afford di-tert-butyl [5-(5-chloro-2-hydroxyphenyl)-1,2-benzoxazol-3-yl]imidodicarbonate as a colorless solid in 63% yield (2.69 g): 1H NMR (300 MHz, DMSO-d6) δ7.66 (m, 2H), 7.47-7.45 (s, 1H), 7.22-7.19 (m, 3H), 6.90-6.87 (m, 1H), 1.41 (s, 18H); MS (ES+) m/z 460.9 (M+1), 462.9 (M+1).

1. temperatureThe mixture was heated
2. temperatureat reflux for 5 h
3. concentrationconcentrated in vacuo
4. additionThe residue was diluted with ethyl acetate (75 mL)
5. washwashed with water (2×40 mL)
6. dry with materialdried over anhydrous sodium sulfate
7. filtrationfiltered
8. concentrationconcentrated in vacuo
9. customThe residue was purified by column chromatography
10. washeluting with a 10-50% gradient of ethyl acetate in hexanes