Sodium borohydride → 5,8-dichloro-3,4-dihydroisoquinolin-1(2H)-one

Participants

Reaction Conditions

Reaction Steps

Cobalt (II) chloride hexahydrate (166 g, 0.70 mol) was added to a room temperature solution of ethyl 3,6-dichloro-2-(cyanomethyl)benzoate (253d, 90 g, 0.35 mol) in ethanol (1.5 L), and the resulting mixture cooled to 0° C. Sodium borohydride (66.3 g, 1.74 mol) was added in portions. The mixture was stirred at room temperature for 1 hour, and then refluxed overnight. The resulting suspension was filtered and the filtrate concentrated in vacuo. The solids in the filter cake were stirred in ethyl acetate (600 mL), and then filtered again. This procedure was repeated a second time. The combined filtrates were added to the original filtrate residue, and this organic solution washed with water (800 mL) and saturated aqueous sodium chloride solution (800 mL), dried over sodium sulfate, and concentrated in vacuo to give 5,8-dichloro-3,4-dihydroisoquinolin-1(2H)-one (253e, 29.3 g, 39% yield) as an off-white solid.

Provenance & Evidence