Abstract: The present invention relates to a compound represented by the Formula [I]: Wherein: the A ring is a 5-membered aromatic heterocyclic group containing at least one hetero atom selected from a nitrogen atom, and the like; A1 and A2, are each a nitrogen atom, and the like; X2, X3, X4, and X5 are all carbon atoms, or alternatively any one of X2, X3, X4, and X5 is a nitrogen atom and the rest are all carbon atoms; R1 is a hydrogen atom, or the like; R2, R3, R4, and R5, are each a hydrogen atom, or the like; R6 and R6?, are each a hydrogen atom, and the like; R7 is an aryl group and the like; and R8 is an amino group or a hydroxy group, or a pharmaceutically acceptable salt or ester thereof.