A mixture of 2.96 g of 3-(4-cyanophenyl)-5-methanesulfonyloxymethyl-2-oxazolidinone (m.p. 162°-163°; obtainable by reacting 4-aminobenzonitrile with 2,3-epoxypropanol to give 4-(2,3-dihydroxypropylamino)benzonitrile (oily), reacting with diethyl carbonate/potassium tert-butylate at 110° to give 3-(4-cyanophenyl)-5-hydroxymemthyl-2-oxazolidinone (m.p. 130°-131°) and esterifying with methanesulfonyl chloride), 1.69 g of ethyl piperidine-4-carboxylate, 70 ml of acetonitrile, 1.38 g of potassium carbonate and 1.65 g of potassium iodide is boiled for 25 h. After customary working up, ethyl 1-(3-(4-cyanophenyl)-2-oxo-5-oxazolidinylmethyl)piperidine-4-carboxylate ("IA") is obtained, FAB 358.
