Prebiotic synthesis: phosphorylation in aqueous solution

Formation of uridine-5'-phosphate from uridine and inorganic phosphate in aqueous solution is effected by the following condensing agents: cyanogen, cyanoformamide, cyanate, cyanamide, thioformate, ethylisocyanide, and a watersoluble carbodiimide. The yields are always small, even when a large excess of condensing agent is used. The cyclization of uridine-3'-(2')-phosphate occurs under the same conditions but in much greater yield.