Synthesis
General procedure for the synthesis of 6-iodoquinazoline from quinazoline: N-iodosuccinimide (NIS, 5.4 g, 24 mmol) was slowly added to a solution of quinazoline (2.1 g, 16.13 mmol) in concentrated sulfuric acid (16 mL) at 0 °C. The reaction mixture was stirred at 0 °C for 10 min before gradually warming to room temperature and continued stirring for 15 h. The reaction mixture was then mixed with NIS (2.4 g, 16.13 mmol). Subsequently, NIS (2.0 g, 8.9 mmol) was added supplementally and the mixture was continued to stir for 5 hours. After completion of the reaction, the mixture was slowly poured into crushed ice (80 g) and stirred for 1 hour. The resulting solution was filtered, the pH was adjusted to 7 with concentrated ammonia and stirred for another 1 hour at 0°C. It was filtered again and the solids were washed with ice-cold water. Finally, the solid was air dried to give 6-iodoquinazoline (3.4 g, 87% yield). The product was confirmed by 1H NMR (400 MHz, DMSO) and mass spectrometry (MS ESI m/z 256 [M+H]+, C6H3IN4).
