Ethanol → 5-Nitro-1H-pyrrolo[2,3-b]pyridine-2-carboxylic acid

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Reaction Steps

A flask is charged successively with 5 g (22.62 mmol) of methyl 5-nitro-1H-pyrrolo[2,3-b]pyridine-2-carboxylate (Azasynth), 50 mL of 95% ethanol, 50 mL of water and 1.63 g (67.92 mmol) of lithium hydroxide. The reaction mixture is refluxed for 30 minutes and then left to return to room temperature. The solution is concentrated under reduced pressure and then diluted in 200 mL of water. The aqueous phase is extracted with 3×60 mL of ethyl acetate, then acidified with 32% hydrochloric acid until the pH is between 2 and 3. The precipitate formed is filtered, rinsed with 50 mL of ethyl acetate and then dried under vacuum for 6 h. 2.45 g of a white solid is obtained (52%).

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