Water → 7-Bromoimidazo[1,2-a]pyridine-3-carboxylic acid

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Reaction Steps

Ethyl 7-bromoimidazo[1,2-a]pyridine-3-carboxylate (15 g, 56 mmol) and lithium hydroxide monohydrate (3 g, 71.4 mmol) were mixed with a 1:2:1 mixture of tetrahydrofuran/ethanol/water (560 mL). The mixture was stirred at ambient temperature for 16 hours. The solvent was removed under vacuum to give a yellow gum. Water (300 mL) and dichloromethane were added and the phases were separated. The aqueous phase was cooled in an ice-water bath before adjusting the pH to 3 using 2N sulfuric acid. The product precipitated, was collected by filtration and was washed with a small amount of water (50 mL) then dried under vacuum to give 7-bromoimidazo[1,2-a]pyridine-3-carboxylic acid (8.3 g) as an off-white solid.

Provenance & Evidence