An achiral nucleotide analog based on barbituric acid has been synthes
ized. The analog, which is 5,5-di(2-phosphoethyl)barbituric acid, unde
rgoes extensive oligomerization in aqueous solution, when activated, t
o produce pyrophosphate-linked chains. In contrast to a number of othe
r bisphosphorylated nucleoside analogs which have been studied, the co
mpound has little tendency to cyclize. The possible prebiotic implicat
ions are discussed.