A mixture of 20 parts of 1-(2-bromoethyl)-4-nitrobenzene, 21.8 parts of N-[4-(methoxymethyl)-4-piperidinyl]-N-phenylpropanamide, 14.4 parts of N,N-diethylethanamine and 270 parts of N,N-dimethylacetamide is stirred and heated for 4.50 hours at 70° C. The reaction mixture is cooled to room temperature and poured onto water. The product is extracted with methylbenzene. The extract is washed with water, dried, filtered and evaporated. The oily residue is purified by column-chromatography over silica gel using a mixture of trichloromethane and 4% of methanol as eluent. The first fraction is collected and the eluent is evaporated, yielding a first fraction of 14 parts of N-{4-(methoxymethyl)-1-[2-(4-nitrophenyl)ethyl]-4-piperidinyl}-N-phenylpropanamide; mp. 98.7° C The second fraction is collected and the eluent is evaporated. The residue is purified once more by column-chromatography over silica gel using a mixture of trichloromethane and 4% of methanol as eluent. The pure fraction is collected and the eluent is evaporated, yielding a second fraction of 2.8 parts of N-{4-(methoxymethyl)-1-[2-(4-nitrophenyl)ethyl]-4-piperidinyl}-N-phenylpropanamide; mp. 98.7° C.
