Water → 1-[2-(tert-Butoxycarbonyl-methyl-amino)-ethyl]-6-chloro-1H-indole-3-carboxylic acid

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Reaction Steps

To a solution of 15.4 g (38.0 mmol) crude {2-[6-chloro-3-(2,2,2-trifluoro-acetyl)-indol-1-yl]-ethyl}-methyl-carbamic acid tert-butyl ester in 380 ml N,N-dimethylformamide were slowly added 11.0 g (228 mmol) sodium hydride (50%, dispersion in oil) followed by 3.40 ml (190 mmol) water at 15-22° C. After stirring for 1 h at room temperature 500 ml water were added slowly. The mixture was washed with two 300-ml portions of tert-butyl methyl ether. The combined organic layers were extracted with 300 ml of a 0.5 M aqueous solution of sodium hydroxide. The combined aqueous layers were acidified to pH 2 with an ice-cold 4 M aqueous solution of hydrochloric acid at 0-5° C. and extracted with two 400-ml portions of ethyl acetate.

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