Morphinan derivative and medical usage thereof

A morphinan derivative represented by the general formula (I) below or a pharmaceutically acceptable acid addition salt thereof for use in treatment of drug dependence

• [wherein L1 -L2-L3 represents C(R9)—CH2—CH2, C(R9)—CH═CH, or C═CH—CH2, wherein R9 represents a hydrogen atom, hydroxy, nitro, C1-C5 alkanoyloxy, C1-C5 alkoxy, C1-C5 alkyl, amino, monoalkylamino (the alkyl moiety has one to five carbon atoms), dialkylamino (the alkyl moiety has one to five carbon atoms), C1-C5 alkanamide, benzamide, or C7-C14 aryl-alkanamide;
• A represents —C(═O)— or —SO2—;
• R1 represents C1-C7 linear or branched alkyl, C3-C6 cycloalkyl, C4-C7 cycloalkylalkyl, C4-C6 cycloalkenyl, C5-C7 cycloalkenylalkyl, C7-C13 aralkyl, C4-C7 alkenyl, allyl, styryl, anilino, or an organic group containing any of basic skeletons (II) below, wherein, in the basic skeletons (II), * represents the point of attachment;
• said organic group represented by R1 is optionally substituted by at least one substituent selected from the group consisting of C1-C5 alkyl, C1-C5 alkoxy, C1-C5 alkanoyloxy, hydroxy, fluorine, chlorine, bromine, iodine, amino, monoalkylamino (the alkyl moiety has one to five carbon atoms), dialkylamino (the alkyl moiety has one to five carbon atoms), nitro, cyano, carboxy, carbamoyl, N,N-dialkylcarbamoyl (the alkyl moiety has one to five carbon atoms), amidino, guanidino, isothiocyanate, trifluoromethyl, phenyl, trifluoromethoxy, and methylenedioxy;
• both R2 and R3 represent a hydrogen atom, or one of R2 and R3 represents a hydrogen atom and the other represents hydroxy, or R2 and R3 together represent oxo;
• R4 represents a hydrogen atom, hydroxy, C1-C5 alkoxy, C3-C7 alkenyloxy, C7-C13 aralkyloxy, or C1-C5 alkanoyloxy;
• R5 and R6 together represent —O—, —S—, or -CH2-, or R6 represents a hydrogen atom and R5 represents a hydrogen atom, hydroxy, C1-C5 alkoxy, or C1-C5 alkanoyloxy;
• R7 represents a hydrogen atom, C1-C5 alkyl, C2-C5 alkenyl, or C7-C13 aralkyl;
• B1 represents—N(R10) C(═O)— or —NR10—, wherein R10represents a hydrogen atom, C1-C5 linear or branched alkyl;
• B2 represents a valence bond, C1-C14 linear or branched alkylene (provided that said alkylene is optionally substituted with at least one substituent selected from the group consisting of C1-C5 alkoxy, C1-C5 alkanoyloxy, hydroxy, fluorine, chlorine, bromine, iodine, amino, monoalkylamino (the alkyl moiety has one to five carbon atoms), dialkylamino (the alkyl moiety has one to five carbon atoms), nitro, cyano, carboxy, carbamoyl, amidino, guanidino, trifluoromethyl, phenyl and phenoxy;
• and one to three methylene groups are optionally replaced with carbonyl groups), C2-C14 linear or branched acyclic unsaturated divalent hydrocarbon group containing one to three double and/or triple bonds (provided that said hydrocarbon group is optionally substituted with at least one substituent selected from the group consisting of C1-C5 alkoxy, C1-C5 alkanoyloxy, hydroxy, fluorine, chlorine, bromine, iodine, amino, monoalkylamino (the alkyl moiety has one to five carbon atoms), dialkylamino (the alkyl moiety has one to five carbon atoms), nitro, cyano, carboxy, carbamoyl, amidino, guanidino, trifluoromethyl, trifluoromethoxy, phenyl, and phenoxy;
• and one to three methylene groups are optionally replaced with carbonyl groups), or C1-C14 linear or branched saturated or unsaturated divalent hydrocarbon group containing one to five thioether bonds, ether bonds, and/or amino bonds (—N(H)—) (provided that the hetero atom comprised in said thioether bond, ether bond, or amino bond is not directly linked to B1;
• and one to three methylene groups are optionally replaced with carbonyl or sulfonyl groups);
• R8 represents a hydrogen atom or an organic group containing any of basic skeletons (III) below, wherein, in the basic skeletons (III), * represents the point of attachment;
• Q represents N, O, or S;
• said organic group represented by R8 is optionally substituted by at least one substituent selected from the group consisting of C1-C5 alkyl, C1-C5 alkoxy, C1-C5 alkanoyloxy, hydroxy, fluorine, chlorine, bromine, iodine, amino, monoalkylamino (the alkyl moiety has one to five carbon atoms), dialkylamino (the alkyl moiety has one to five carbon atoms), nitro, cyano, isothiocyanate, trifluoromethyl, phenyl, phenoxy, trifluoromethoxy, and methylenedioxy;
• and
• said general formula (I) inclusively represents the (+)-form, the (−)-form, and the (±)-form of the molecule].