Disclosed are 8,9-dihydroimidazo[1,2-a]pyrimido[5,4-e]pyrimidin-5(6H)-one compounds, specifically represented by the Formula I:or a pharmaceutically acceptable salt or prodrug thereof, wherein A and R1-R7 are defined herein. Compounds having Formula I are Wee1 kinase inhibitors. Therefore, compounds of the disclosure may be used to treat diseases caused by abnormal Wee1 activity.