In a 1 L round bottom flask, 55 g of sodium ethoxyzine acetate (1.05 eq., 0.26 mol) and 26 g of formamidine acetate (1 eq., 0.25 mol) were added to a 500 mL aqueous solution containing 10 g of sodium hydroxide. The reaction mixture was stirred at room temperature for 16 hours. Subsequently, concentrated hydrochloric acid was added slowly and dropwise to the reaction mixture until the pH dropped to 1, at which point fine solids precipitated. The mixture was continued to be stirred at 0°C for 1 hour to complete the precipitation. The solid product was collected by filtration and washed sequentially with water and ether. The resulting white solid was dried in a vacuum oven preheated to 40°C for 20 hours. Finally, grinding in methanol afforded the target compound 6-hydroxy-4-pyrimidinecarboxylic acid in 25% yield.1H NMR (dβ-DMSO) data were as follows: δ 12.88 (1H, OH), 8.24 (s, 1H), 6.83 (s, 1H).
