General procedure for the synthesis of 2-amino-5-pyrimidinecarboxaldehyde from methyl 2-aminopyrimidine-5-carboxylate: methyl 2-aminopyrimidine-5-carboxylate (300 mg, 2.0 mmol) was dissolved in methanol (5 mL) containing a few drops of water. Subsequently, lithium hydroxide (122 mg, 5.1 mmol) was added and the reaction mixture was stirred and reacted at 60 °C overnight. Upon completion of the reaction, the mixture was concentrated under reduced pressure, after which it was diluted with water and the pH was adjusted with 1 M HCl solution to 4. At this point, 2-aminopyrimidine-5-carboxylic acid precipitated as a white solid, which was isolated by vacuum filtration to give the product (244 mg, 90% yield). The structure of the product was confirmed by 1H NMR (DMSO-d6), δ: 12.73 (1H, broad peak), 8.63 (2H, single peak), 7.44 (2H, broad peak).
