Ethanol → 2-Tert-butyl-5-nitro-1H-indole-7-carboxylic acid

Participants

Reaction Steps

2-tert-Butyl-5-nitro-1H-indole-7-carbonitrile (4.6 g, 19 mmol) was added to a solution of KOH in EtOH (10%, 100 mL) and the mixture was heated at reflux overnight. The solution was evaporated to remove alcohol, a small amount of water was added, and then the mixture was acidified with dilute hydrochloric acid. Upon standing in the refrigerator, an orange-yellow solid precipitated, which was purified by chromatography on silica gel (15% EtOAc in petroleum ether) to afford 2-tert-butyl-5-nitro-1H-indole-7-carboxylic acid (4.0 g, 77%). 1H NMR (CDCl3, 300 MHz) δ 10.79 (brs, 1 H), 8.66 (s, 1 H), 8.45(s, 1 H), 6.57 (s, 1 H), 1.39 (s, 9 H).

Provenance & Evidence