Pyridine → 5-(1-Benzyloxycarbonyl-4-piperidyl)pentylp-toluenesulfonate

To a chilled mixture of 5-(1-benzyloxycarbonyl-4-piperidyl)pentanol (18 g) and pyridine (150 ml) is added portionwise tosyl chloride (14.6 g) for 30 minutes with stirring. After stirring for further 1 hour at ice-bath temperature, ice water (2 ml) is added dropwise and the resulting mixture is dissolved in ethyl acetate (500 ml). This solution is washed successively with 2N hydrochloric acid (500 ml), 1N hydrochloric acid (500 ml×2), sodium bicarbonate solution and water. The organic layer is dried over anhydrous magnesium sulfate and concentrated in vacuo. The oily residue is purified by silica gel column chromatography using hexane-ethyl acetate (3:1-2:1) to give 5-(1-benzyloxycarbonyl-4-piperidyl)pentyl p-toluenesulfonate (18 g) as an oil.