Sodium hydride → ethyl 1-(2-tert-butoxycarbonylaminoethyl)-4-methyl-1H-indole-2-carboxylate

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Reaction Steps

A mixture of ethyl 4-methyl-1H-indole-2-carboxylate (42.9 g, 211 mmol), 60% sodium hydride (9.29 g, 232 mmol) and N,N-dimethylformamide (300 ml) was stirred at room temperature for 1 hour. A solution of 2-tert-butoxycarbonylaminoethyl 4-toluenesulfonate (86.6 g, 275 mmol) in N,N-dimethylformamide (200 ml) was added dropwise and the resulting mixture was stirred at room temperature for 9 hours. The reaction mixture was poured into ice water and extracted twice with ethyl acetate, and the extract solution was washed with a 5% aqueous sodium chloride solution and dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure and the resulting residue was purified by a silica gel column chromatography (eluent: ethyl acetate/n-hexane=3/97) to obtain 24.4 g of ethyl 1-(2-tert-butoxycarbonylaminoethyl)-4-methyl-1H-indole-2-carboxylate.

Provenance & Evidence