The present invention relates to a compound represented by the formula
wherein A is a benzene ring optionally having substituents, R
1
, R
2a
and R
3
are each a hydrogen atom, a hydrocarbon group optionally having substituents or a heterocyclic group optionally having substituents, R
1
and R
2a
may form a ring via X, when R
1
and R
2a
form a ring via X, R
1
and R
2a
are each a bond or a divalent C
1-5
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 R
1
, R
2a
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.