Hydrochloric Acid → 7-nitro-1H-indole-2-carboxylic acid

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Reaction Steps

7-Nitro-1H-indole-2-carboxylic acid methyl ester (13 g, 59 mmol) prepared in Preparation 17 was dissolved in a solvent mixture of tetrahydrofuran and water (1:1, 300 mL), to which was added 1N aqueous sodium hydroxide solution (180 mL, 177 mmol). The mixture was stirred for 3 h at room temperature, and excess 6N hydrochloric acid solution was added thereto. The reaction mixture was extracted with ethyl acetate. The extract was washed with saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, and filtered. The solvent was removed by distillation under reduced pressure, and the residue was dried to give the title compound (12 g, Yield 99%).

Provenance & Evidence