Acetic Acid → Ethyl 6-chloroindole-2-carboxylate

Participants

Reaction Steps

To crude 3-(4-chloro-2-nitro-phenyl)-2-oxo-propionic acid ethyl ester (151 mmol) in ethanol:glacial HOAc (1:1, v/v, 560 mL) at rt was added iron powder (74.4 g) and the reaction mixture was stirred at reflux for 4 h. The mixture was filtered and evaporated to give a residue which was redistributed in dichloromethane/1N HCl. The organic layer was washed with 1N HCl, NaHCO3, and brine and dried. Evaporation followed by crystallization (DCM) gave 6-Chloro-1H-indole-2-carboxylic acid ethyl ester as a pale yellow solid (16.8 g, 50% over 2 steps).

Provenance & Evidence