Sodium Hydroxide → 6-nitro-1H-indole-2-carboxylic Acid

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Reaction Steps

4.4 g (20 mmol) 6-Nitro-1H-indole-2-carboxylic acid methyl ester (190) was dissolved in 80 mL methanol and was treated with 30 mL 1M NaOH overnight at 55 C°. The methanol was evaporated, the remaining aqueous solution was diluted to 100 mL and was acidified to pH 2 using concentrated HCl. The precipitate was filtered off, washed three times with water then dried to give 3.92 g (95%) 191 as yellow powder. The NMR was consistent with the structure. 191 was used without further purification.

Provenance & Evidence