Hydrochloric Acid → 5,6-Difluoroindoline

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Reaction Steps

Under an argon atmosphere 0.30 g (1.8 mmol) 5,6-difluoro-1,3-dihydro-indol-2-one were dissolved in 10 mL THF and 3.0 mL of a 1 M borane in THF solution were added dropwise. Then the reaction mixture was heated for 2 h to 70° C. and then cooled. After the addition of 3 mL MeOH a further 5 mL of a 4N aqueous hydrochloric acid solution were added and the mixture was refluxed for 1 h. The organic phase was evaporated down, the aqueous phase was washed with DCM and then made alkaline with a 4N aqueous sodium hydroxide solution and extracted several times with EtOAc. The combined organic phases were dried on sodium sulphate, filtered and evaporated down.

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