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

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Reaction Steps

5-Nitro-1H-pyrrolo[2,3-b]pyridine-2-carboxylic acid methyl ester (6 g, 27.1 mmoles) was dissolved in methanol/water mixture (1/1). Potassium hydroxide (3 eq) was added and the mixture was heated at reflux overnight. After cooling down, the mixture was acidified until pH=3 by hydrochloric acid 3N. The precipitate was filtered off, washed with water, then diethyl ether, and dried under vacuum. A brownish solid, 5-nitro-1H-pyrrolo[2,3-b]pyridine-2-carboxylic acid, is obtained (5.47 g). Yield=98%. ESI-MS: m/z 208 ([M+H]+). HPLC purity: 100%

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