The present invention relates to a compound represented by the formula wherein A is a
benzene ring optionally having substituents, R1, R2a and R3 are each a
hydrogen atom, a
hydrocarbon group optionally having substituents or a heterocyclic group optionally having substituents, R1 and R2a may form a ring via X, when R1 and R2a form a ring via X, R1 and R2a are each a bond or a
divalent C1-5 acyclic
hydrocarbon group optionally having substituents, and X is a bond, an
oxygen atom, an optionally oxidized
sulfur atom or an imino group optionally having a
substituent, provided that R1, R2a and X are not bonds at the same time, or a salt thereof, and an agent for inhibiting
kinase (
phosphorylation enzyme), which contains this compound or a
prodrug thereof. The compound of the present invention has an inhibitory activity against
kinase such as a
vascular endothelial growth factor receptor (VEGFR) and the like, and is useful as an agent for the prophylaxis or treatment of
cancer and the like.