3-Cyano-2-methylthio-4,8-dioxo-9H-pyrimido[1,2-a]pyrimidine was reacted with various heterocyclic amines (nitrogen nucleophiles) such as pyrrolidine, piperidine, morpholine, piperazine, and differently substituted phenols (oxygen nucleophiles) in the presence of dimethyl formamide and potassium carbonate as a catalyst to afford the corresponding 2-substituted derivatives of the title compound. The structures of the products were confirmed through infrared, nuclear magnetic resonance, and mass spectral data.. KEYWORDS :Dimethyl formamide, Hetaryl amines, Oxygen nucleophiles, Potassium carbonate, Spectral data.