Chemical evolution from hydrogen cyanide: photochemical decarboxylation of orotic acid and orotate derivatives

Irradiation of solutions at pH 7 to pH 8.5 of orotic acid, orotidine, and orotidine 5'-phosphate with light at 254 nanometers yields the corresponding uracil derivative via the singlet excited state. This reaction completes a plausible prebiotic synthesis of uracil and its derivatives starting from HCN as the only carbon source.