A compound represented by the general formula (I) or a pharmaceutically acceptable salt thereof: ** Formula ** in which R1 represents a hydrogen atom, a C1-C6 alkyl group, a hidoxy group (C1-C6 alkyl), a group (C1-C6 alkoxy) - (C1-C6 alkyl), a hydroxy group (C1-C6 alkoxy) - (C1-C6 alkyl), a group (C1-C6 alkyl) amino- (C1-C6 alkyl), a hydroxy (C1-C6 alkyl) amino- (C1-C6 alkyl) group, a [N- (C1-C6 alkyl) -N-hydroxy (C1-C6 alkyl) amino] - (C1-C6 alkyl) group, a group (C1-C6 alkyl) sulfonylamino- (C1-C6 alkyl), a group [N- (C1-C6 alkyl) -N- (C1-C6 alkyl) sulfonylamino] - (C1-C6 alkyl), a carboxy group ( C1-C6 alkyl), a halogen group (C1-C6 alkyl), a group (C3-C8 cycloalkyl) - (C1-C6 alkyl), a C2-C6 alkenyl group, a C2-C6 alkynyl group, a C3 cycloalkyl group -C8, a C3-C8 cycloalkenyl group, a hydroxy group, a C1-C6 alkoxy group, a hydroxy group (C1-C6 alkoxy), a group (C1-C6 alkoxy) - (C1-C6 alkoxy), a group ( C1-C6 alkyl) sulfonyl- (alco xi C1-C6), a carboxy group (C1-C6 alkoxy), a halogen group (C1-C6 alkoxy), a C1-C6 alkylthio group, a C1-C6 alkylsulfinyl group, a C1-C6 alkylsulfonyl group, an amino group , a C1-C6 alkylamino group, a di (C1-C6 alkyl) amino group, a hydroxy (C1-C6 alkyl) amino group, an N- (C1-C6 alkyl) -N-hydroxy group (C1-C6 alkyl) amino, a formylamino group, a group (C1-C6 alkyl) carbonylamino, a carboxy group, a group (C1-C6 alkoxy) carbonyl, a carbamoyl group, a group (C1-C6 alkylamino) carbonyl, a di (C1 alkyl group -C6) aminocarbonyl, a cyano group, a halogen group, a phenyl group, a substituted phenyl group, in which the substituent or substituents represent 1 to 4 groups independently selected from the substituent group α, an aromatic heterocyclyl group of 5 or 6 members, an aromatic heterocyclyl group of 5 or 6 substituted members, in which the substituent or substituents represent 1 to 4 groups independently selected from The substituent group α, a saturated 5- or 6-membered heterocyclyl group, a substituted 5- or 6-membered saturated heter
