The present invention relates to a compound represented by the formula:wherein W is C(R1) or N, each A is an optionally substituted aryl group or a heteroaryl group, X1is －NR3－Y1－, －O－, －S－, －SO－, －SO2－ or －CHR3－ wherein R3is a hydrogen atom or an optionally substituted aliphatic hydrocarbon group, or R3is optionally bonded to A to form an optionally substituted ring structure, R1is a hydrogen atom or an optionally substituted group bonded via a carbon atom, a nitrogen atom or an oxygen atom, R2is a hydrogen atom or optionally substituted group bonded via a carbon atom or a sulfur atom, or R1and R2, or R2and R3are optionally bonded to form an optionally substituted ring structure, or a salt thereof, and a tyrosine kinase inhibitor or an agent for the prophylaxis or treatment of cancer, which contains this compound or a prodrug thereof.本發明係關於一種下式表示之化合物或其鹽其中W為C(R1)或N，各個A為選擇性經取代之芳基或雜芳基，X1為－NR3－Y1－、－O－、－S－、－SO－、－SO2－或－CHR3－，其中R3為氫原子或選擇性經取代之脂肪族烴基，或R3為選擇性鍵結至A以形成選擇性經取代之環結構，R1為氫原子或透過碳原子、氮原子或氧原子鍵結之選擇性經取代之基團，R2為氫原子或透過碳原子或硫原子鍵結之選擇性經取代之基團，或R1與R2或R2與R3係選擇性鍵結以形成選擇性經取代之環結構；以及本發明係關於一種含有此化合物或其前藥之酪胺酸激酶抑制劑或癌症之預防或治療劑。
