1H-Indole-5-Carboxylic Acid → Tert-butyl 1H-indole-5-carboxylate

Participants

Reaction Steps

0.50 g (3.10 mmol) indole-5-carboxylic acid is suspended in 20 ml absolute benzene and heated under reflux. A solution of 2.80 g (12.39 mmol) 90% N,N-dimethylformamidedi-tert-butylacetal in 20 ml absolute benzene is added drop-wise within 30 min. Following another heating under reflux for 30 minutes and subsequent cooling, the reaction mixture is diluted with diethyl ether, washed with 5% sodium carbonate solution and with saturated NaCl solution. Drying on sodium sulfate, filtration and concentration on the rotary evaporator leave as a crude product a yellow oil which is purified on silica gel by means of column chromatography (flow agent: petroleum ether/ethyl acetate 95:5) and yields the product as a white solid.

Provenance & Evidence