1,4-Dioxane hydrochloride → 2H-Pyran-4-ol, 4-[[4-(aminomethyl)-1-piperidinyl]methyl]tetrahydro-

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Reaction Steps

To a solution of tert-butyl ({1-[(4-hydroxytetrahydro-2H-pyran-4-yl)methyl]piperidin-4-yl}methyl)carbamate as prepared in 1(3) (50.28 g, 153 mmol) in methanol (100 mL) was added 4N hydrochloric acid dioxane solution (200 mL, 800 mmol) at room temperature. After 4 h, the volatile materials were removed by evaporation. The resulting amorphous was precipitated with diethyl ether/methanol (v/v=5/1). The precipitate was collected and added to the ice cooled 6N aqueous sodium hydroxide solution (200 mL) gradually. The mixture was extracted with dichloromethane/methanol (v/v=10/1, 500 mL×4). The combined organic layers were washed with brine, dried over magnesium sulfate and concentrated in vacuo to give 24.90 g (99%) of the title compound as a pale brown amorphous solid.

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