The general procedure for the synthesis of 2-amino-4-iodopyrimidine using 2-amino-4-chloropyrimidine as starting material was as follows: 2-amino-4-chloropyrimidine (13.0 g, 100 mmol) was slowly added to 57 wt% aqueous hydriodic acid solution (115 mL, 1.00 mol) at 0 °C. The reaction mixture was stirred continuously for 3 hours at room temperature. Subsequently, the mixture was cooled to 0 °C and the resulting precipitate was removed by filtration. The filter cake was transferred to a pre-cooled aqueous 5 N Na2CO3 solution (200 mL). The aqueous phase was extracted using ethyl acetate (3 × 500 mL), and the combined organic phases were concentrated under reduced pressure to afford 2-amino-4-iodopyrimidine (21.1 g, 95.0 mmol, 95% yield) as a white solid. The product was characterized by 1H NMR (400 MHz, DMSO-d6): δ 7.78 (d, J = 5.0 Hz, 1H), 7.02 (br.s, 2H), 7.00 (d, J = 5.0 Hz, 1H). The mass spectrum (ESI, cation mode) showed m/z: 222.1 ([M + H]+).
