反应详情

温度

90 °C

A stirred mixture of methyl 5,6-diaminonicotinate (1.69 g, 10.12 mmol) from Step 1 of this Example, formic acid (0.5 mL), and triethylorthoformate (25 mL) was heated at 90° C. for 2.5 h. The reaction mixture was cooled to rt and then the precipitated solid was collected by filtration and dried to afford methyl 3H-imidazo[4,5-b]pyridine-6-carboxylate (588 mg, 33%) as a cream solid which did not require further purification. The filtrate was concentrated under reduced pressure, and the residue purified by silica gel flash chromatography eluting with 100% DCM to 10% MeOH in DCM to afford additional methyl 3H-imidazo[4,5-b]pyridine-6-carboxylate (550 mg, 31%) as a cream solid. 1H NMR (300 MHz, DMSO-d6) δ 13.33 (br s, 1H), 8.95 (d, J=1.5 Hz, 1H), 8.64 (s, 1H), 8.50 (d, J=1.5 Hz, 1H), 3.91 (s, 3H). LCMS (ESI) m/z 178 (M+H)+.

1. temperatureThe reaction mixture was cooled to rt
2. filtrationthe precipitated solid was collected by filtration
3. customdried