6-Cyclohexylmethoxy-5-(cyano-NNO-azoxy)pyrimidine-4-amine: A new scaffold endowed with potent CDK2 inhibitory activity

Substitution of the cyano-NNO-azoxy moiety (NC-N=(O)N-) for the nitroso group in NU6027, a potent and selective CDK2 inhibitor, affords a compound with slightly improved potency and comparable selectivity profile. A molecular modelling study indicates for this new scaffold a binding mode similar to the one adopted by other purine and pyrimidine analogues, and suggests a relevant role for a conserved water molecule in stabilizing the bioactive pose of this and other pyrimidine ligands. The introduction of aminosulfonylphenyl substituents on the 2-amino group of the pyrimidine increased the CDK2 inhibitory potency by two orders of magnitude, while maintaining the same degree of selectivity.