To a solution of 15.0 g benzyl 1-piperazinecarboxylate in 100 ml dichloromethane were added 20.7 ml triethylamine. The solution was cooled to 0° C. and 8.4 ml propylchloroformate added dropwise at this temperature. After stirring for 1 h the reaction mixture was diluted with dichloromethane and washed with 0.1 M HCl and saturated NaHCO3. The crude product obtained after evaporation of the solvent was purified by flash chromatography on silica using an ethyl acetate/heptane gradient. Yield: 19.3 g.
