Patent ID: 8263649

Claim:
A compound represented by general formula (I), or a pharmaceutically acceptable salt thereof: wherein R 1 is a hydrogen atom, C 1 -C 6 alkyl group, C 2 -C 6 alkyl ketone group or —(CH 2 ) n -Q, of which Q is an ether group or amine group substituted with C 1 -C 6 lower alkyl group; R 2 is a hydrogen atom, or an ether group or thio group substituted with C 1 -C 6 alkyl group; R 3 is wherein R′ is a hydrogen atom, or C 1 -C 6 alkyl group, X is O, S or amine group unsubstituted or substituted with R″, of which R″ is benzyl ester or carboxyl group, n is an integer of 0-9; with the proviso that compound 3-[2-(3,4-dimethoxy-phenyl)-benzofuran -5-yl]propan-1-ol is excluded from the general formula I.