Hydrochloric Acid → 5-Bromoisoindoline

Participants

Reaction Conditions

Reaction Steps

564.2 ml of a 1M borane/THF solution are added dropwise to 42.5 g (188 mmol) of 5-bromoisoindole-1,3-dione in 300 ml of THF (dry) at −5° C. over a period of 60 min. The mixture is subsequently stirred for 2 h at 22° C. and then for 16 h at 80° C. The mixture is then cooled to 0° C., before 200 ml of methanol (exothermic!) and 200 ml of 2M hydrochloric acid are slowly added. The resultant mixture is stirred for 3 h at 80° C., cooled to 22° C., and 100 ml of water are added. The aqueous solution is extracted three times with 150 ml of dichloromethane each time, dried over sodium sulfate, filtered and evaporated to dryness: 5-bromo-2,3-dihydro-1H-isoindole; yield 15.4 g of “13” (41.3%); MW 198.06; Rt 1.099 min (“polar” method).

Provenance & Evidence