Treatment of ethyl 2-chloro-4-trifluoromethylpyrimidine-5-carboxylate (I) with hydrazine in THF gives the hydrazinopyrimidine (II). This is subsequently condensed with citraconic anhydride (III) in boiling chloroform to produce the N-(dioxopyrrolidinyl)aminopyrimidine (IV). Finally, N-alkylation of (IV) by means of iodomethane and NaH furnishes the title compound.