for ar is substituted by at least two cf 3 groups for example the following compounds further preferred are compounds wherein the phenyl group for ar is substituted by at least one cf 3 group for example the following compounds rac 2 ethyl n 1 methyl 3 phenyl piperidin 3 yl 4 trifluoromethyl benzamide rac 2 bromo 6 methoxy n 1 methyl 3 phenyl piperidin 3 yl 4 trifluoromethyl benzamide rac n 1 2 dimethyl 3 phenyl piperidin 3 yl 2 methoxy 6 methylsulfanyl 4 trifluoromethyl benzamide rac 2 cyclopropyl n 1 methyl 3 phenyl piperidin 3 yl 4 trifluoromethyl benzamide rac 2 methoxy n 1 methyl 3 phenyl piperidin 3 yl 6 methylsulfanyl 4 trifluoromethyl benzamide rac n 1 methyl 3 phenyl piperidin 3 yl 2 methylsulfanyl 4 trifluoromethyl benzamide rac n 3 4 fluoro phenyl 1 methyl piperidin 3 yl 2 methoxy 6 methylsulfanyl 4 trifluoromethyl benzamide rac n 3 4 chloro phenyl 1 methyl piperidin 3 yl 2 methoxy 6 methylsulfanyl 4 trifluoromethyl benzamide 2 methoxy n u2014 s 1 methyl 3 phenyl piperidin 3 yl 6 methylsulfanyl 4 trifluoromethyl benzamide 2 methoxy n u2014 r 1 methyl 3 phenyl piperidin 3 yl 6 methylsulfanyl 4 trifluoromethyl benzamide rac 2 difluoromethoxy n 1 methyl 3 phenyl piperidin 3 yl 4 trifluoromethyl benzamide rac n 3 3 chloro phenyl 1 methyl piperidin 3 yl 2 methoxy 6 methylsulfanyl 4 trifluoromethyl benzamide rac 2 methoxy n 3 4 methoxy phenyl 1 methyl piperidin 3 yl 6 methylsulfanyl 4 trifluoromethyl benzamide rac n 5 fluoro 1 methyl 3 phenyl piperidin 3 yl 2 methoxy.