| abstract |
2,2-Diphenylbutanamide derivatives represented by the general formula (1) or salts thereof: (1) [wherein A is (CH2)n- (wherein n is 1 or 2) or methine (CH); when A is CH2-, B is methine or nitrogen and the bond between A and B is single; when A is (CH2)2-, B is nitrogen and the bond between A and B is single; and when A is methine, B is quaternary carbon and the bond between A and B is double; R1 and R2 are each independently hydrogen, lower alkyl, or cycloalkyl, or alternatively R1 and R2 together with the nitrogen atom adjacent thereto may form a heterocycle; and Ar is optionally substituted phenyl, a bicyclic aromatic ring group, a mono- or bi-cyclic heterocyclic group, or a fluorene group]. These derivatives exhibit excellent ยต-opioid agonism and analgesic activity against neurogenic pain and are useful as drugs including peripherally acting analgesic and neurogenic pain controller. |