Fused pyrimidine compounds having a saturated, unsaturated or aromatic A ring fused to a pyrimidine ring and having a complex substituents at the 2 position and a substituted amine at the 4 position of the pyrimidine ring as well as optional aliphatic, functional and/or aromatic components substituted at other positions of the pyrimidine ring and A ring are disclosed. These compounds are inhibitors of the AAA proteasome complex containing p97 and are effective medicinal agents for treatment of diseases associated with p97 bioactivity such as cancer.