Ethyl 3-(4-cyano-2-nitrophenyl)-2-oxopropanoate → Ethyl 6-cyano-1H-indole-2-carboxylate

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Reaction Steps

To a suspension of 3-(4-cyano-2-nitro-phenyl)-2-oxo-propionic acid ethyl ester (1.21 g, 4.62 mmol) in acetic acid (50 mL) and water (8 mL) add zinc powder (1.81 g, 27.7 mmol) portionwise over 2 h. Stir at rt for 3 h then filter to remove the solids. Concentrate the filtrate to a volume of 10 mL, dilute with EtOAc (40 mL), and filter again to remove insoluble material. Concentrate the filtrate to give the desired product 6-cyano-1H-indole-2-carboxylic acid ethyl ester as a solid (670 mg, 3.13 mmol).

Provenance & Evidence