Pyruvic Acid → 6-Chloro-5-(ethoxycarbonyl)-1H-indole-2-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

A solution of ethyl 4-amino-2-chloro-5-iodobenzoate (1.82 g, 5.59 mmol) in N,N-dimethylformamide (18 ml) under argon was admixed with pyruvic acid (1.27 ml, 18.2 mmol) and 1,4-diazabicyclo[2.2.2]octane, evacuated and flooded with argon. Then argon was passed through the solution for 5 min, and then palladium(II) acetate (68 mg, 0.30 mmol) was added and the mixture was heated to 100° C. for 2 h. The cooled solution was filtered through Celite and the filtercake was rinsed with ethyl acetate (100 ml). The filtrate (suspension) was washed with hydrochloric acid (2 M; 2×25 ml) and with water (2×25 ml), dried over sodium sulphate and filtered. The filtrate was concentrated to dryness under reduced pressure and gives a red-brown solid (1.93 g, approx. 51% product), which was used for the next step without further purification.

Provenance & Evidence