Hydrochloric Acid → 5-fluoro-3-methyl-2,3-dihydro-1H-indole

Participants

Reaction Conditions

Reaction Steps

Under an argon atmosphere 18 mL (18 mmol) of a 1M borane in THF solution was added dropwise to 1.5 g (9.1 mmol) 5-fluoro-3-methyl-1,3-dihydro-indol-2-one in 50 mL THF. The reaction mixture was stirred for 2 h at 70° C., cooled to 0° C. and combined with 10 mL methanol and then with 30 mL semi-concentrated hydrochloric acid solution. The reaction mixture was refluxed for 1 h with stirring, cooled and the organic phase was eliminated using the rotary evaporator. The aqueous phase was extracted with ethyl acetate. The aqueous phase was made alkaline with an aqueous 4M sodium hydroxide solution and extracted with dichloromethane. The organic phase was dried on sodium sulphate, filtered off and evaporated down.

Provenance & Evidence