Acetic Acid → 4-Amino-5-chloro-2-methyl-indole-1-carboxylic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

5-Chloro-2-methyl-4-nitro-indole-1-carboxylic acid methyl ester (2.1 g, 7.81 mmol) is dissolved in ethanol (40 ml) and glacial acetic acid (40 ml). Iron powder (1.74 g, 31.26 mmol, activated previously with H2SO4 conc and then washed with water) is added, and the reaction mixture is heated to 85° C. for 90 minutes. The reaction mixture is poured into water and stirred at RT for 30 minutes, after which a slightly brownish colored precipitate forms which is filtered off. After washing with water and drying, the title compound is obtained in pure form. 1H NMR (DMSO, 400 MHz, 120° C.) δ 2.51 (s, 3H), 4.05 (s, 3H), 5.0-5.2 (br s, 2H), 6.66 (s, 1H), 7.05 (d, J=9 Hz, 1H), 7.31 (d, J=9 Hz, 1H); ES-MS: 238 [M+H]+.

Provenance & Evidence