Patent ID: 7423185

Claim:
A compound represented by general formula (I): a prodrug thereof, or a pharmaceutically acceptable salt thereof, wherein each of R 1 and R 2 is independently a hydrogen atom or a lower alkyl group; each of R 3 , R 4 , R 5 and R 6 is independently a hydrogen atom, a halogen atom, a lower alkyl group or a lower alkoxy group; each of R 7 and R 8 is independently a hydrogen atom, a halogen atom, a lower alkyl group, a halo-lower alkyl group, a hydroxy-lower alkyl group, a cycloalkyl group, a heterocycloalkyl group, a lower alkoxy group, a di(lower alkyl)amino group, a cyclic amino group, a di(lower alkyl)amino-lower alkyl group, an aryl group, an aryloxy group, an aralkyloxy group, a heteroaryl group, a cyano group, a hydroxyl group, a lower acyl group, a lower alkylsulfanyl group, a lower alkylsulfonyl group, a carboxy group, a lower alkoxycarbonyl group or an aralkyloxycarbonyl group, or when R 7 and R 8 are adjacent each other, R 7 and R 8 are bonded together to form —O—(CH 2 ) m —O—, —O—(CH 2 ) n — or —(CH 2 ) p —, wherein m is an integer of 1 to 3, n is an integer of 2 to 4, p is an integer of 3 to 5; R 9 is —C(O)—R 10 , -A 1 -C(O)—R 10 , —O-A 2 -C(O)—R 10 or a tetrazol-5-yl group, wherein R 10 is a hydroxyl group, a lower alkoxy group, an aralkyloxy group or —NR 11 R 12 , each of R 11 and R 12 is independently a hydrogen atom, a lower alkyl group, a carboxy-lower alkyl group or a lower alkoxycarbonyl-lower alkyl group, or R 11 and R 12 , together with the nitrogen atom to which they are bonded, form a cyclic amine, A 1 is a lower alkylene group or a lower alkenylene group, and A 2 is a lower alkylene group.