4,6-diamino-2-bromonicotinonitrile

109-77-3

42530-03-0

The general procedure for the synthesis of 4,6-diamino-2-bromo-3-cyanopyridine from malononitrile was as follows: HBr gas was bubbled into a mixture of malononitrile (16.3 g, 0.247 mol) and toluene (400 mL) for 2 hr at 0 °C, and a pale yellow precipitate was formed during the reaction. Subsequently, the reaction mixture was heated to 100 °C and maintained for 2 h, during which a large amount of gas production was observed. Upon completion of the reaction, it was cooled to room temperature and the yellow solid product was separated by diafiltration and washed with toluene and subsequently dried in air. The resulting solid (25.96 g) was mixed with water (500 mL) and the pH of the suspension was adjusted to 9-10 with NH4OH (~15 mL, concentration ~15%). the mixture was stirred at room temperature for 1 hr and the mixture was filtered. The product was purified by recrystallization from EtOH to give a yellow solid. Finally, it was dried in a vacuum oven at 60 °C to obtain 4,6-diamino-2-bromo-3-cyanopyridine (12.95 g, 49% yield). The structure of the product was confirmed by 1H NMR (DMSO): δ 6.67 (2H, brs), 6.55 (2H, brs), 5.59 (1H, s).