5-(2-Dimethylamino-vinyl)-2,4-dinitro-benzoic acid ethyl ester → Ethyl 6-amino-1H-indole-5-carboxylate

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Reaction Steps

A mixture of 5-(2-dimethylamino-vinyl)-2,4-dinitro-benzoic acid ethyl ester (15 g, 0.05 mol) and Raney Ni (5 g) in EtOH (500 mL) was stirred under H2 (50 psi) at room temperature for 2 h. The catalyst was filtered off and the filtrate was concentrated to dryness. The residue was purified by column chromatography on silica gel to give 6-amino-1H-indole-5-carboxylic acid ethyl ester (B-25) (3 g, 30%). 1H NMR (DMSO-d6) δ 10.68 (s, 1H), 7.99 (s, 1H), 7.01-7.06 (m, 1H), 6.62 (s, 1H), 6.27-6.28 (m, 1H), 6.16 (s, 2H), 4.22 (q, J=7.2 Hz, 2H), 1.32-1.27 (t, J=7.2 Hz, 3H).

Provenance & Evidence