Pyrrole-3-carboxylic acid → tert-butyl 1H-pyrrole-3-carboxylate

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Reaction Steps

0.50 g (4.50 mmol) pyrrole-3-carboxylic acid is suspended in 15 ml absolute benzene and boiled under reflux. A solution 4.07 g (18.0 mmol) 90% N,N-dimethylformamidedi-tert-butylacetal in 15 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 saturated NaCl solution. Drying on sodium sulfate, filtration and concentration on the rotary evaporator leave as a crude product a yellow solid which is purified on silica gel by means of column chromatography (flow agent: petroleum ether/ethyl acetate 90:10) and yields the product as a white solid.

Provenance & Evidence