In the title compound, C(14)H(15)N(5)O(2), the whole mol-ecule apart from the terminal C atoms of the isopropyl group is located on a crystallographic mirror plane. An intra-molecular C-H⋯N hydrogen-bonding inter-action may stabilize the mol-ecular conformation. The crystal packing features weak slipped π-π inter-actions between the pyrimidine and the phenyl rings of symmetry-related mol-ecules [centroid-centroid distance = 3.746 (1)Å, slippage of 1.574 Å].