Structure-based design of 2-arylamino-4-cyclohexylmethyl-5-nitroso-6-aminopyrimidine inhibitors of cyclin-dependent kinases 1 and 2.

A series of O(4)-cyclohexylmethyl-5-nitroso-6-aminopyrimidines bearing 2-arylamino substituents was synthesised and evaluated for CDK1 and CDK2 inhibitory activity. Consistent with analogous studies with O(6)-cyclohexylmethylpurines, 2-arylaminopyrimidines with a sulfonamide or carboxamide group at the 4'-position were potent inhibitors, with IC(50) values against CDK2 of 1.1+/-0.3 and 34+/-8 nM, respectively. The crystal structure of the 4'-carboxamide derivative, in complex with phospho-Thr160 CDK2/cyclin A, confirmed the expected binding mode of the inhibitor, and revealed an additional interaction between the carboxamide function and an aspartate residue.