The present invention relates to a compound represented by the formula:wherein A is pyridyl group having at leastone substituent wherein R1, R2 and R3 are each a hydrogen atom, a halogenatom, a C1-6 alkyl group optionally substituted byhalogen or a C1-6 alkoxy group optionally substituted by halogen, R4 and R6are each a hydrogen atom, a halogen atom or a C1-6 alkylgroup optionally substituted by halogen, R5 is a hydrogen atom, a halogenatom, a C1-6 alkyl group optionally substituted by halogenor a C1-6 alkoxy group optionally substituted by halogen, and R7 is a hydrogenatom or a C1-6 alkyl group optionally substitutedby halogen or a salt thereof, or a pharmaceutical composition containing thesame.
