Hydrochloric Acid → HCID 86675794, compound

Participants

Reaction Steps

To a solution of calcium chloride (81 g) in ethanol (147 mL) was added sodium borohydride (6.93 g) at 5° C., and the mixture was stirred at the same temperature for 30 min. To the reaction mixture was added dropwise at 5° C. a solution of ethyl 5-[(tert-butoxycarbonyl)amino]-1,4-dimethyl-1H-indole-2-carboxylate (195 g) obtained in Reference Example 44 in THF (1.2 L), and the mixture was stirred at the same temperature for 30 min and at room temperature for 15 hr. While maintaining the reaction mixture at 20° C. or below, 1N hydrochloric acid (1.4 L) was added dropwise to adjust to pH 3, and water (1 L) and saturated aqueous sodium hydrogen carbonate (190 mL) were added. The organic solvent was evaporated under reduced pressure and the residual aqueous layer was extracted with ethyl acetate. The extract was washed with saturated brine, dried over magnesium sulfate, and concentrated under reduced pressure. The precipitated solid was washed with ethyl acetate (200 mL) and petroleum ether (600 mL), and dried under reduced pressure to give the title compound (134 g, yield 79%) as colorless crystals.

Provenance & Evidence