2.23 g (10.0 mmol) of 4,5,6-triaminopyrimidine sulfate was added in small portions to a solution of 1.68 g (20.0 mmol) sodium bicarbonate in 50 mL of water with vigorous stirring. A brisk evolution of CO2 gas was observed. The resulting suspension was heated to 80° C. and 2.42 g (10 mmol) of 3,3′-dihydroxybenzil was added to the mixture. The reaction mixture was refluxed for 1 hour, during which time the starting materials completely dissolved and the product precipitated out as a light-yellow solid.
