The object of the present invention is to provide a compound having an antagonistic action against µ-opioid receptors, which causes less side effects and thus is highly safe.A compound represented by the general formula (I), or a pharmacologically acceptable salt thereof:whereinR1 and R2 are the same or different, and each represents a hydrogen atom or a halogen atom, provided that R1 and R2 are not simultaneously halogen atoms,R3 represents a C1-C3 alkyl group or a vinyl group, andR4 represents the formula (II):wherein R5 represents a hydroxy group or a C1-C3 alkoxy group, and R6 and R7 are the same or different, and each represents a hydrogen atom or a halogen atom；or the formula (III):wherein Ring A represents a halogen atom(s)-substituted C5-C7 cycloalkyl group which is optionally substituted by a C1-C3 alkoxy group, or a halogen atom(s)-substituted 5- to 7-membered saturated heterocyclic group.
