Ethyl 6-(1-benzyloxycarbonyl-4-piperidyl)-2-chlorohexanoate → Ethyl 6-(4-piperidyl)hexanoate

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Reaction Steps

In 200 ml of ethanol is dissolved 10 g of ethyl 6-(1-benzyloxycarbonyl-4-piperidyl)-2-chlorohexanoate, and a catalytic reduction reaction is carried out at ordinary temperature and at atmospheric pressure using 5 g of 10% palladium-carbon (50% in water) as a catalyst. After absorption of hydrogen stops, the catalyst is removed by filtration, and the filtrate is concentrated under reduced pressure to give ethyl 6-(4-piperidyl)hexanoate. Water (100 ml) and 200 ml of ethyl acetate are added to this product, and 10 g of sodium hydrogencarbonate is added to the mixture, followed by stirring. Benzyloxycarbonyl chloride (7.2 ml) is added dropwise to the mixture at room temperature, followed by stirring overnight. The ethyl acetate layer is separated, dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The residue is purified by silica-gel column chromatography (hexane:ethyl acetate=4:1) to give 7.7 g of ethyl 6-(1-benzyloxycarbonyl-4-piperidyl)hexanoate as a colorless oily material.

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