反应详情

1-phenylmethyl-3-methoxy-4,4-dimethoxypiperidine (4b, 2.22g, 8.36 mmol) from Example 2 and p-toluenesulfonic acid (3.15 g, 16.6 mmol) was heated to reflux in acetone (100ml) for three hours. After being cooled, the reaction solution was concentrated under vacuum, then slurried in 40ml of 10% sodium hydroxide solution. The aqueous mixture was extracted with 2×60 ml of ether, the combined organic layers were dried over magnesium sulfate, then concentrated under vacuum. The crude residue was purified by chromatography (silica gel; ethyl acetate/hexane; 1:1) to provide the intermediate 1-phenylmethyl-3-methoxy-4-piperidone (5b, 1.66 g, 90%).

1. temperatureAfter being cooled
2. concentrationthe reaction solution was concentrated under vacuum
3. extractionThe aqueous mixture was extracted with 2×60 ml of ether
4. dry with materialthe combined organic layers were dried over magnesium sulfate
5. concentrationconcentrated under vacuum
6. customThe crude residue was purified by chromatography (silica gel; ethyl acetate/hexane; 1:1)