HCID 86736580、化合物 → HCID 13192236、化合物

14.0 g (0.036 mol) of trans-3-hydroxy-4-phenylthio-1-(β,β,β-trichloroethoxycarbonyl)-piperidine are dissolved in 140 ml of 90% acetic acid and the solution is treated with 9.5 g (0.14 mol) of zinc dust in portions. The reaction mixture is subsequently stirred for one hour at room temperature and then filtered through a layer of diatomaceous earth. The filtrate is evaporated under a high vacuum, the resulting residue is taken up in 500 ml of water, the solution is cooled to 0° in an ice-water bath and, at this temperature, rendered strongly alkaline with concentrated sodium hydroxide solution and the reaction mixture is extracted by shaking with 3 times 200 ml of methylene chloride. The combined organic phases are washed once with water, dried over sodium sulphate and evaporated under a water pump vacuum, whereupon trans-3-hydroxy-4-phenylthio-piperidine is obtained in the form of the crystalline crude base, which is recrystallised from methanol/ether; melting point 135°-136°. The neutral fumarate prepared from the base with fumaric acid crystallises from methanol/ether; melting point 171°-173°.