Besides known reduction and solvent addition products, the photolysis of 1,3-dimethyluracil in methanol resulted in formation of the enamine 2-methoxycarbonyl-N-methyl-3-methylaminopropenamide (5) a novel ring-opening reaction. A mechanism for the formation of 5 is suggested and its structure was confirmed by an independent synthesis. ... M. Arys and J. Eriksen, to be published. ... In ppm relative to TMS at 0 ppm. ... In some cases an enhanced yield of 5 was noted upon ...