Acetic Acid → Methyl 4-{1-[2-(4-cyanophenyl)ethyl]-4-hydroxypiperidin-4-ylmethoxy}benzoate

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Reaction Steps

Acetic acid (11.5 mL) was added to a dichloromethane solution (450 mL) of the compound (17.7 g) obtained in Step 6 and the compound (19.4 g) obtained in Step 1 of Example 1 at room temperature and the mixture was stirred at the same temperature for thirty minutes. Sodium triacetoxyborohydride (56.6 g) was added to the mixture under cooling with ice-water and the mixture was stirred at the same temperature for thirty minutes and further stirred at room temperature for five hours. The solvent was removed under reduced pressure and insoluble matter (16.1 g) precipitated by adding water (250 mL) and ethyl acetate (250 mL) was collected by filtration. To the obtained insoluble matter (13.0 g) was added water (50 mL) and saturated aqueous sodium hydrogencarbonate solution (150 mL) and the residue was extracted with ethyl acetate. The organic layer was washed with brine and dried over anhydrous sodium sulfate, and the solvent was removed under reduced pressure. The obtained residue was crystallized from ether-hexane to obtain the titled compound (10.3 g) as crystals. The physical data of the obtained compound accord with those of the compound of Example 3.

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