反应详情

To a stirred mixture of 4-bromo-5-methoxybenzene-1,2-diamine (3.8 g, 18 mmol) from Step 1 of this Example and triethyl orthoformate (50 mL) was added formic acid (1 mL). The mixture was heated at reflux for 3 h, then concentrated under reduced pressure. The residue was partitioned between EtOAc (200 mL) and a 1 N aq Na2CO3 (100 mL). The EtOAc layer was separated, washed with brine (100 mL), dried over Na2SO4, filtered, and concentrated under reduced pressure to afford 5-bromo-6-methoxy-1H-benzo[d]imidazole (4.0 g) as a brown oil. The material was used in the next step without further purification. LCMS (ESI) m/z 228 and 230 (M+H)+.

1. temperatureThe mixture was heated
2. temperatureat reflux for 3 h
3. concentrationconcentrated under reduced pressure
4. customThe residue was partitioned between EtOAc (200 mL)
5. customThe EtOAc layer was separated
6. washwashed with brine (100 mL)
7. dry with materialdried over Na2SO4
8. filtrationfiltered
9. concentrationconcentrated under reduced pressure