反应详情

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.

1. temperatureheated
2. temperatureunder reflux
3. temperatureunder reflux for 30 minutes
4. washwashed with 5% sodium carbonate solution and with saturated NaCl solution
5. customDrying on sodium sulfate, filtration and concentration on the rotary evaporator
6. customleave as a crude product a yellow oil which
7. customis purified on silica gel by means of column chromatography (flow agent: petroleum ether/ethyl acetate 95:5)