A compound of formula (I) wherein R3 to R5, G, B, and Z, are as defined in the claims, and pharmaceutically acceptable salts thereof are disclosed. The compounds of formula (I) possess utility as FGFR inhibitors and are useful in the treatment of a condition, where FGFR kinase inhibition is desired, such as cancer.本發明揭示一種式(I)化合物,其中R3至R5、G、B及Z係如申請專利範圍中所定義,及其醫藥學上可接受之鹽。式(I)化合物具有作為FGFR抑制劑之效用且適用於治療需要FGFR激酶抑制之病狀(諸如癌症)。