Potassium Carbonate → (3S)-1-(2-hydroxyethyl)-3-(2-indolylcarbonylamino)-1,3-dihydro-5-phenyl-2H-1,4-benzodiazepine-2-one

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Reaction Steps

A mixture of (3S)-1-(2-acetoxyethyl)-3-(2-indolylcarbonylamino)-1,3-dihydro-5-phenyl-2H-1,4-benzodiazepine-2-one (1.80 g) and potassium carbonate (0.30 g) in 85% aqueous ethanol (30 ml) was heated at 65° to 70° C. for 1 hour under stirring. After cooling, ethanol was removed under reduced pressure, and to the residue was added water. The aqueous mixture was acidified with dilute hydrochloric acid and extracted with ethyl acetate. The extract was washed with brine and dried over magnesium sulfate. Removal of the solvent afforded a light yellow amorphous powder, which was chromatographed on silica gel with an eluent of a mixture of chloroform and ethyl acetate (3:1). The fractions containing the desired product were combined and evaporated to give (3S)-1-(2-hydroxyethyl)-3-(2-indolylcarbonylamino)-1,3-dihydro-5-phenyl-2H-1,4-benzodiazepine-2-one (1.47 g) as a colorless amorphous powder.

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