In the title compound, C(18)H(23)N(5)O(2), the triazolopyrimidine ring system is essentially planar, with a maximum displacement of 0.032 (2) Å, and forms a dihedral angle of 87.59 (15)° with the phenyl ring. In the crystal, mol-ecules are linked by inter-molecular C-H⋯O hydrogen bonds and C-H⋯π inter-actions into chains parallel to the c axis.