Oxalyl chloride → Methyl 7-bromoimidazo[1,2-a]pyridine-3-carboxylate

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Reaction Steps

7-bromoimidazo[1,2-a]pyridine-3-carboxylic acid (4.93 g, 20.5 mmol) was dissolved in 80 mL of dry dichloromethane. To this solution was added oxalyl chloride (20.5 mL, 40.9 mmol, 2M in dichloromethane) followed by a few drops of DMF. The mixture was stirred at ambient temperature for 16 hours, then concentrated under reduced pressure. The resulting material was taken up in 100 mL of methanol and stirred at ambient temperature for 6 hours, then concentrated under reduced pressure. The resulting material was suspended in saturated aqueous sodium bicarbonate, extracted with dichloromethane and EtOAc. The organics were combined, dried over sodium sulfate and concentrated under reduced pressure to give 4.63 g (89%) of the title compound.

Provenance & Evidence