Agent for treating hcv infection

A therapeutic method for HCV infectious disease comprising administration of a compound represented by formula (I):

• wherein R1 represents a hydrogen atom, a halogen atom or C1-6 alkyl,
• R2 represents a hydrogen atom, C1-6 alkyl or C1-6 alkoxy-C1-4 alkyl,
• R3 represents a hydrogen atom, C1-6 alkyl or C1-6 alkoxy-C1-4 alkyl,
• R4 represents a hydrogen atom, a halogen atom, C1-6 alkyl, C1-6 alkoxy, C3-6 cycloalkoxy, C1-6 alkylsulfonyl, C1-6 alkoxy-C1-4 alkyl, hydroxy(C1-6)alkyl, halo(C1-6)alkyl, amino, formyl C2-4 alkanoyl, nitro or cyano, and
• R5 represents a group represented by the formula:
• or a group shown in the following table:
• #
• R5
• 1
• 2
• 3
• 4
• 5
• 6
• 7
• 8
• 9
• 10
• 11
• 12
• wherein R6 represents indanyl, chromanyl, picolyl, C7-15 aralkyl, C3-6 cycloalkyl-C1-4 alkyl or N—C7-15 aralkylamino,
• optionally having a substituent selected from the group consisting of halogen atom(s), C1-6 alkyl, halo(C1-6)alkyl, C1-6 alkoxy, C3-6 cycloalkylene, pyrazolyl and C6-14 aryl,
• and R7 represents a hydrogen atom, C1-6 alkyl or hydroxy(C1-6)alkyl, or R6 and R7, together with the nitrogen atom to which they are bonded, represent a group shown in the following table:
• #
• —N(R6)(R7)
• 1
• 2
• 3
• or a pharmaceutically acceptable salt thereof.