反应详情

温度

100 °C

A stirred mixture of 6-bromopyridine-2,3-diamine (1.30 g, 6.91 mmol) from Step 1 of this Example, formic acid (0.7 mL), and triethylorthoformate (28 mL) was heated at 100° C. for 1.5 h. After the reaction mixture was cooled to rt, the mixture was concentrated under reduced pressure. The residue was triturated with a mixture of 5% MeOH in DCM. The solid was collected by filtration and dried to afford 5-bromo-3H-imidazo[4,5-b]pyridine (245 mg, 18%) as a tan solid which did not require further purification. The filtrate was concentrated under reduced pressure, and the residue was purified by silica gel flash chromatography (eluting with 100% DCM to 10% MeOH in DCM) to afford additional 5-bromo-3H-imidazo[4,5-b]pyridine (756 mg, 55%) as a tan solid. 1H NMR (300 MHz, DMSO-d6) δ 13.08 (br s, 1H), 8.50 (s, 1H), 8.00 (d, J=8.3 Hz, 1H), 7.43 (d, J=8.3 Hz, 1H). LCMS (ESI) m/z 198 and 200 (M+H)+.

1. temperatureAfter the reaction mixture was cooled to rt
2. concentrationthe mixture was concentrated under reduced pressure
3. customThe residue was triturated with a mixture of 5% MeOH in DCM
4. filtrationThe solid was collected by filtration
5. customdried