General procedure for the synthesis of (2-aminopyrimidin-5-yl)methanol from 2-amino-5-pyrimidinecarboxaldehyde: To a stirred solution of 2-amino-5-pyrimidinecarboxaldehyde (500 mg, 4.06 mmol) in methanol (6 mL) was added sodium borohydride (200 mg, 5.28 mmol) in batches. The reaction mixture was slowly warmed up to 0 °C, followed by returning to room temperature and continued stirring for 3 hours. The progress of the reaction was monitored by thin layer chromatography (TLC) (unfolding agent: dichloromethane solution in 5% methanol, Rf value 0.3). Upon completion of the reaction, the reaction was quenched by the addition of saturated aqueous ammonium chloride solution and the mixture was concentrated under reduced pressure. The residue was directly upsampled onto a short silica gel column (100-200 mesh) and eluted using a gradient from dichloromethane to a dichloromethane solution containing 7.5% methanol. The eluate containing the target product was collected and concentrated to give (2-aminopyrimidin-5-yl)methanol as a light yellow solid (340 mg, 67% yield). The product was confirmed by 1H NMR (400 MHz, DMSO-d6): δ 8.16 (s, 2H), 6.50 (br s, 2H), 4.99 (t, 1H), 4.26 (d, 2H).GCMS (m/z): 125.0.
