反应详情

温度

40 °C

1,2,3,4,11,11a-Hexahydro-2-benzyl-4-methyl-pyrazino[1,2-b]isoquinolin-6-one (from Isomer B, 12 mg, 0.04 mmol) and 10% palladium on carbon (5 mg) in MeOH (1 ml) was stirred under a balloon of hydrogen. The catalyst was filtered off and then fresh catalyst added. After stirring an additional 4 h at 40° C. under a balloon of hydrogen, the reaction was filtered through Celite® rinsing with methanol to afford 8 mg of crude product. Column purification (Chiralcel OD, 10% 1/1 MeOH/EtOH in hexanes) afforded pure (4R,11aR)-1,2,3,4,11,11a-hexahydro-2,4-dimethyl-pyrazino[1,2-b]isoquinolin-6-one (1.5 mg, 17% yield) MS (ESI) 231 (M+H). Further elution afforded (4S,1 aS)-1,2,3,4,11,11a-hexahydro-2,4-dimethyl-pyrazino[1,2-b]isoquinolin-6-one (1.6 mg, 18% yield) MS (ESI) 231 (M+H). Further elution also provided (4R,11aR)-1,2,3,4,11,11a-hexahydro-4-methyl-pyrazino[1,2-b]isoquinolin-6-one (2.4 mg, 29% yield) and (4S,11aS)-1,2,3,4,11,11a-hexahydro-4-methyl-pyrazino[1,2-b]isoquinolin-6-one (2.2 mg, 27% yield).

1. filtrationThe catalyst was filtered off
2. additionfresh catalyst added
3. filtrationthe reaction was filtered through Celite®
4. washrinsing with methanol
5. customto afford 8 mg of crude product
6. customColumn purification (Chiralcel OD, 10% 1/1 MeOH/EtOH in hexanes)