Patent ID: 8211907

Claim:
A compound of the formula (I) or a pharmaceutically acceptable salt thereof: wherein Ring A represents a benzene ring, R 1 represents C 1-6 alkyl which may be substituted with one or more groups selected from the group consisting of —OH, —O—C 1-6 alkyl, amino which may be substituted with one or two C 1-6 alkyl, and oxo; —O—C 1-6 alkyl; halogen; cyano; or cyclic amino, n represents an integer of 0 to 4, R 2 represents —H or C 1-6 alkyl, R 3 represents C 1-6 alkyl which may be substituted with phenyl, cycloalkyl, or —H, R 4 represents C 1-6 alkyl which may be substituted with one or more groups selected from the group consisting of —OH, —O—C 1-6 alkyl, amino which may be substituted with one or two C 1-6 alkyl, oxo, and cyclic amino, X 1 represents —CH 2 — or —CH(R 0 )—, X 2 represents —C(R A )(R B )—, X 3 represents —C(R C )(R D )—, m represents an integer of 1 to 3, R 0 represents —H, or R 0 is combined with R 4 to represent C 3-5 alkylene, and, R A , R B , R c , and R D independently represent —H or C 1-6 alkyl, wherein, in the case where m represents 2 or 3, each of R C and R D may be the same as or different from each other, and provided that 2-(1,2,3,4,5,9b-hexahydro-4aH-indeno[1,2-b]pyridin-4a-yl)-N,N-dimethylethaneamine is excluded.