A One-Pot Synthesis of 5-(1,3-Dimethyl-2,6-Dioxo-5-{[(1E)-Arylmethylene]Amino}-1,2,3,6-Tetrahydropyrimidin-4-yl)-1,3,7,9-Tetramethyl-5,10-Dihydropyrimido[5,4-g]Pteridine-2,4,6,8(1H,3H,7H,9H)-Tetrone via a Pseudo Four-Component Domino Reaction

An unexpected pseudo four-component reaction between 5,6-diamino-1,3-dimethyluracil and aldehydes in the presence of a catalytic amount of p-toluenesulfonic acid in ethanol and under mild reaction conditions which led to the synthesis of a novel class of dihydropyrimido[5,4-g]pteridine-2,4,6,8(1H,3H,7H,9H)-tetrones under mild reaction conditions is described. The products can be obtained by simple filtration in moderate to good yields, without the need for further purification. Some of these products revealed interesting photo-physical properties and spectacular fluorescence in solution after UV exposure.