A solution of 3.7 gm (10 m mol) of 4-[(1-(2-piperidinophenyl)-ethyl)-aminocarbonylmethyl]-benzyl chloride [m.p.: 123°-125° C.; prepared from the alcohol described in Example 25 by means of thionyl chloride in chloroform] in 35 ml of absolute ethanol was added dropwise to a solution of sodium malonic acid diethyl ester [prepared from 0.7 gm (30 m mol) of sodium in 25 ml of absolute ethanol and 4.8 gm (30 m mol) of malonic acid diethyl ester]. A catalytic amount of potassium iodide was added, and the mixture was refluxed for 16 hours. After evaporation in vacuo, the evaporation residue was adjusted neutral by means of hydrochloric acid and extracted with methylene chloride. The organic extract was dried over sodium sulfate, filtered, and evaporated in vacuo. The evaporation residue was purified by column chromatography on silica gel (toluene/acetone=6:1).
