30 ml of benzene, 0.4 g (4 mmol) of 3-piperidinol and 1.0 g (4 mmol) of methyl benzilate were put into a 50 ml 3-mouth flask equipped with a stirrer, a reflux condenser, and a molecular sieve 4A (15 g) tube and a soda lime tube for trapping methanol from out of the solvent that drips down through the reflux condensation, and the mixture was refluxed by heating while stirring. After all of the methyl benzilate had dissolved, 20 mg of sodium methoxide (made by Aldrich) was added to the solution and reaction was carried out for 3 hours. After the reaction had been completed, the reaction liquid was cooled to room temperature, and then 50 ml of 1N hydrochloric acid was added, and the organic solvent layer was removed. The aqueous solution layer obtained was washed twice with 50 ml of ether, and was then made basic using a 28% ammonium hydroxide aqueous solution. The aqueous solution was subjected to ether extraction, the ether layer obtained was washed twice with 50 ml of water, and then drying was carried out using anhydrous potassium carbonate. After removing the drying agent, the solvent was evaporated off under reduced pressure, thus obtaining an oily residue, and then this residue was recrystallized from ether-hexane, thus obtaining 0.5 g of (±)3-piperidyl benzilate ((±)3-PB) as crystals (yield 40%).
