反应详情

2-(2,2-Dimethoxy-ethylamino)-N-phenethyl-acetamide hydrochloride (8.77 g, 29.0 mmol) was added to the ice-cooled sulfuric acid (8.8 ml) and the mixture was stirred for 3.5 hours at room temperature. Ice-water was added to the solution after cooling by ice and the resulting solution was extracted with dichloromethane after adjusted to pH 12 with 20% aqueous sodium hydroxide. The organic layer was washed with brine and dried with magnesium sulfate, and then the solvents were removed under reduced pressure. Recrystallization of the residue with hexane-ethyl acetate afforded 1,2,3,6,7,11b-hexahydro-pyrazino[2,1-a]isoquinolin-4-one (4.38 g, 75%).

1. temperatureafter cooling by ice
2. extractionthe resulting solution was extracted with dichloromethane after adjusted to pH 12 with 20% aqueous sodium hydroxide
3. washThe organic layer was washed with brine
4. dry with materialdried with magnesium sulfate
5. customthe solvents were removed under reduced pressure
6. customRecrystallization of the residue with hexane-ethyl acetate