A compound of the following formula: (formula) in which, Ar is an aromatic ring selected from thienyl, thiazolyl, or (group) of which each can be selectively substituted by halogen, N,N-di-C1-6-alkylaminocarbonyl or Y, in which Y is selected from hydrogen, halogen, CONR9R10, (group) SO2R8, in which R8 is C1-6 alkyl, or SO2NR9R10, in which each R9 and R10 separately are selected from hydrogen, C1-6 alkyl, or cyclopropyl, Z is selected from hydroxyl, hydroxymethyl, amino, carbamoyl, sulfonylamino, (group) (group)(C1-C5 alkyl), or (group)(C1-C5 alkyl), in which R2 is hydrogen or halogen; each R3, R4 and R5 separately are hydrogen or methyl, with the proviso that the total number of methyl does not exceed 2; and R6 is selected from C1-4 alkyl, C1-4 alkoxyl-C1-4 alkyl, cyano-C1-4 alkyl, or hydroxy-C1-4 alkyl.
Opioid compounds