Methanol → 1-Benzyl-4,4-dimethoxypiperidin-3-ol

1-Phenylmethyl-4-piperidone (18.92g, 100 mmol) in 40 ml of methanol was added slowly over a period of 15 minutes to a solution of potassium hydroxide (16.83g, 100 mmol) in 150 ml of methanol at 0° C. Iodobenzene diacetate (35.43 g, 110 mmol) was then added to the mixture in portions over a period of thirty minutes. The reaction mixture was stirred at room temperature overnight. The mixture was then concentrated under vacuum to remove the excess of methanol and the crude residue was diluted with a mixture of water (500 ml) and dichloromethane (300 ml). The dichloromethane layer was separated and the aqueous phase was again extracted with 150ml of dichloromethane. The combined organic layers were dried over sodium sulfate and concentrated under vacuum. The crude residue was dissolved in 100 ml of hexane and crystallized. The solid was washed with 30ml of hexane to yield the intermediate 1-phenylmethyl-3-hydroxy-4,4-dimethoxypiperidine (3b, 6.48 g, 25.8%).

1. concentrationThe mixture was then concentrated under vacuum
2. customto remove the excess of methanol
3. additionthe crude residue was diluted with a mixture of water (500 ml) and dichloromethane (300 ml)
4. customThe dichloromethane layer was separated
5. extractionthe aqueous phase was again extracted with 150ml of dichloromethane
6. dry with materialThe combined organic layers were dried over sodium sulfate
7. concentrationconcentrated under vacuum
8. dissolutionThe crude residue was dissolved in 100 ml of hexane
9. customcrystallized
10. washThe solid was washed with 30ml of hexane

ORD record

ord-2c50abefe4c4485bb810e06a0bce0f5a

Source dataset

uspto-grants-1991_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04994471