There are provided compounds which can be used in the treatment of diseases mediated by the autophosphorylation of a PDGF receptor, specifically, compounds which can inhibit neointima formation hypertrophy. The compounds are those represented by formula (I) or pharmacologically acceptable salts or solvates thereof: wherein R1 and R2 represent hydrogen, alkyl or the like; R3, R4, R5, and R6 represent hydrogen, halogen, alkyl, alkoxy or the like; R11 and R12 represent hydrogen, alkyl, alkylcarbonyl or the like; and A represents any one of formulae (i) to (x), provided that compounds wherein R3, R4, R5 and R6 represent hydrogen and A represents group (v) wherein u is 0 (zero) and R19 represents phenyl optionally substituted by halogen, alkyl, or alkoxy are excluded.