Water → 6,7-Dimethyl-5-methoxy-1,2-dihydro-1h-indole

Participants

Reaction Conditions

Reaction Steps

To a solution of 6,7-dimethyl-5-methoxy-1,3-dihydro-2H-indole-2-one (17.5 g, 91.5 mmol) in THF (500 mL) was added dropwise 1M-borane THF complex salt (306 mmol) at 0° C., and the mixture was stirred at 60° C. 3 hours. After ice-cooling, the mixture was added dropwise to water (100 mL). THF was distilled off under reduced pressure, concentrated hydrochloric acid (100 mL) was added, and the mixture was stirred under reflux for 2 hours. After neutralizing with 12N sodium hydroxide under ice-cooling, the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine, dried over sodium sulfate, and purified by small amount silica gel column chromatography (ethyl acetate). The solvent was distilled off under reduced pressure, followed by recrystallization from hexane, to obtain 8.18 g of the title compound.

Provenance & Evidence