Disclosed is N-(5-(4-(3-methyl-1H-pyrazol-5-ylamino)-6-(3-cyclopropyl-3-fluoroazetidin-2-yl)pyrimidin-2-ylthio)pyridin-2-yl)-3,3,3- trifluoropropanamide represented by structural formula (I-21) or a pharmaceutically acceptable salt thereof, which inhibit Aurora protein kinase activity and are suitable for treating a proliferative disorder is selected from melanoma, myeloma, leukemia, lymphoma, neuroblastoma, or a cancer selected from colon, breast, gastric, ovarian, cervical, lung, central nervous system, renal, prostate, bladder, pancreatic, brain, head and neck, kidney, liver, melanoma, sarcoma, or thyroid cancer.
