0.5 g of 4-(2,4-bis(benzyloxy)phenyl)piperidinium chloride is suspended in 5 ml of dimethylformamide and then 0.43 ml of N,N-diisopropylethylamine is added, as is 0.38 g of pyridin-2-ylcarbamic acid 4-nitrophenyl ester in solution in 2 ml of dimethylformamide. The reaction mixture is stirred for 24 hours at 80° C. It is heated at 80° C. for 24 hours. 50 ml of water are added, and the reaction mixture is then extracted with 50 ml of ethyl acetate. The solvents are evaporated off and then the residue is chromatographed on silica gel (70/30 heptane/ethyl acetate). 20 mg of 4-(2,4-bis(benzyloxy)phenyl)piperidine-1-carboxylic acid pyridin-2-ylamide are obtained.
