Water → 5-Fluoro-1,2,3,4-tetrahydroisoquinoline

Participants

Reaction Steps

5-Fluoro-3,4-dihydro-2H-isoquinolin-1-one (200 mg, 1.2 mmol) was dissolved in anhydrous tetrahydrofuran (6 ml), and the solution was mixed with Red-Al (Aldrich, 65% toluene solution, 6.1 mmol) and stirred at roar temperature for 18 hours. Water was slowly added to the reaction solution, and celite filtration was carried out when foaming started. The reaction product was extracted from the filtrate with ethyl acetate, and the reaction product was extracted from the extract with dilute hydrochloric acid. The water layer was alkalified with sodium hydroxide aqueous solution, and the reaction product was extracted therefrom with ethyl acetate. The extract was washed with saturated brine and dried with anhydrous magnesium sulfate, and then the solvent was removed by evaporation under a reduced pressure to obtain crude 5-fluoro-3,4-dihydro-2H-isoquinoline. The crude 5-fluoro-3,4-dihyrdro-2H-isoquinoline was dissolved in anhydrous N,N-dimethylformamide (3 ml), and the solution was mixed with 2a-(4-bromobutyl)-2a,3,4,5-tetrahydro-1H-benz[cd]indol-2-one (370 mg, 1.2 mmol) and potassium carbonate (250 mg, 1.8 mmol) and stirred at room temperature for 18 hours. The reaction solution was mixed with water, the reaction product was extracted with ethyl acetate, and the extract was washed with water and saturated brine and dried with anhydrous magnesium sulfate. The solvent was removed by evaporation from the extract under a reduced pressure, and the thus obtained material was separated and purified by a silica gel column chromatography to obtain 55 mg (0.14 mmol, 12% in yield) of the title compound.

Provenance & Evidence