反应详情

The crude 5-bromo-4-chlorobenzo[c][1,2,5]oxadiazole 1-oxide (3.2 g, 12.8 mmol) was stirred in 50 ml ethanol, treated with triethyl phosphite (3.2 g, 19 mmol) and heated to reflux for 5 h. After cooling, the volatiles were removed by rotary evaporation, the residue was taken up in 75 mL dichloromethane and stirred with 20 mL bleach solution for 20 min. The organic phase was washed with 10 mL saturated NaCl, dried (Na2SO4) and evaporated. The crude material was purified by flash chromatography on silica to give the title compound as an orange solid (1.5 g, 50%): mp 96-97° C.; 1H NMR (400 MHz, CDCl3) δ 7.68 (d, J=9.4 Hz, 1H), 7.59 (d, J=9.3 Hz, 1H); EIMS m/z 232.

1. temperatureheated
2. temperatureto reflux for 5 h
3. temperatureAfter cooling
4. customthe volatiles were removed by rotary evaporation
5. washThe organic phase was washed with 10 mL saturated NaCl
6. dry with materialdried (Na2SO4)
7. customevaporated
8. customThe crude material was purified by flash chromatography on silica