General procedure for the synthesis of 4-amino-6-iodopyrimidine from 4-amino-6-chloropyrimidine: a mixture of 4-amino-6-chloropyrimidine (1.00 g, 7.72 mmol), sodium iodide (5.79 g, 38.6 mmol) and 40% hydriodic acid (20 ml) was heated for 30 min at 70 °C. After completion of the reaction, the mixture was cooled to room temperature and filtered to remove the precipitate. The filtrate was partitioned between dichloromethane and saturated sodium bicarbonate solution to separate the organic layer. The organic layer was dried with anhydrous sodium sulfate, filtered and the solvent evaporated to give 4-amino-6-iodopyrimidine (1.2 g, 70% yield). The product was characterized by 1H NMR (400 MHz, DMSO-d6): δ 6.89 (1H, s), 7.04 (2H, br s), 8.04 (1H, s).
