A mixture of (±)-1-[3,5-bis(trifluoromethyl)benzoyl]-2-[[3-fluoro-5-(trifluoromethyl)phenyl]methy]-4-piperidinone (0.01 mol) and N-(2,6-dimethylpheny)-1-piperazine-acetamide (0.01 mol) in 2-propanol (150 ml) was hydrogenated at 50° C. with platinum on activated carbon (55), 2 g) as a catalyst in the presence of titanium(IV)isopropoxide (2.84 g) and thiophene solution (1 ml). After uptake of hyrogen, the catalyst was filtered off and the filtrate was evaporated. The residue was taken up in CH2Cl2 and H2O. The organic layer was separated, washed several times with H2O, dried, filtered over dicalite and the solvent was evaporated. This fraction was purified by HPLC over silica gel (eluent: CH2Cl2/CH3OH 98/2). Two pure factions were collected and their solvents were evaporated. The residue was dried, yielding 0.72 g (10%) of (±)-cis-4-[1-[3,5-bis(trifluoromethyl)benzoyl]-2-[[3fluoro-5-(trifluoromethyl)phenyl]methyl]-4-piperidinyl]-N_(2,6-dimethylphenyl)-1-piperazineacetamide (compound 140 ) and 0.88 g (12%) of (±)-trans-4-[1-[3,5-bis(trifluoromethyl)benzoyl]-2-[[3-fluoro-5-(trifluoro-methyl)phenyl]methyl]-4-piperidinyl]-N_(2,6-dimethylphenyl)-1-piperazineacetamide (compound 141).
