Dimethyl Sulfate → 5-Methoxy-1,2-dihydroisoquinolin-1-one

Participants

Reaction Steps

To 3.0 g (18.6 mmol) of 1,5-dihydroxyisoquinoline in 80 ml methanol and 20 ml of water was added 0.78 g of 50% sodium hydroxide (39 mmol) and 2 ml of dimethyl sulfate. The mixture was heated under reflux for two hours. An additional 4.0 ml of dimethyl sulfate and 10 ml of 50% sodium hydroxide was then added and refluxing continued for an additional hour. The mixture was diluted with 200 ml of water and concentrated to half the original volume. The resulting solid was collected and washed with water. Recrystallization from ethanol gave 2.1 g (64%) of the desired product; mp 215°-217°.

Provenance & Evidence