Nitrosation of pyrimidinedione (I) with NaNO2/HCl affords (II), which is further reduced to the diaminopyrimidine (III) by catalytic hydrogenation over Pd/C. Subsequent coupling of (III) with 2,6-di-tert-butyl-4-hydroxycinnamic acid (IV) employing DPP-Cl furnishes the title amide