Synthesis and biological evaluation of 4-(4-aminophenyl)-6-methylisoxazolo[3,4-b] pyridin-3-amine covalent inhibitors as potential agents for the treatment of acute myeloid leukemia

•A series of 4-(4-aminophenyl)-6-methylisoxazolo[3,4-b] pyridin-3-amine derivatives as FLT3 covalent inhibitors were designed and synthesized.•Compound C14 was potent to inhibit FLT3 (IC50 = 256 nM) and had strong inhibitory activity against the human AML cell lines MOLM-13 (IC50 = 507 nM) as well as MV4-11 (IC50 = 325 nM).•The mechanism of C14 against FLT3 was explored.•Compound C14 could be a promising agent for further developing therapeutic remedy for AML.