2-Bromo-7-nitro-5H-pyrrolo[2,3-b]pyrazine synthesis

Yield:1416740-16-3 88.7%

Reaction Conditions:

with sulfuric acid;nitric acid at 10 - 20; for 1.5 h;

Steps:

2.3

Step 3: 2-bromo-7-nitro-5H-pyrrolo[2,3-b]pyrazine[00199] 2-bromo-5H-pyrrolo[2,3-b]pyrazine (20 g, 101.0 mmol) was dissolved in ice-cold sulfuric acid (140.0 mL) , producing a bright orange solution, and concentrated nitric acid (12.73 g, 8.470 mL, 202.0 mmol) was added drop wise with stirring over 30 min keeping the temperature under 10 °C (turning the solution to a clear red colour). The reaction was removed from the ice bath after 30 min and allowed to warm to ambient temperature and left to stir at ambient temperature for 1 hour. The reaction mixture was poured onto ice to obtain a yellow solid. The solid was filtered, washed with water to give 2-bromo-7-nitro-5H- pyrrolo[2,3-b]pyrazine the desired product as a yellow solid. (21.76 g, 88.7%). MS (ES⁺) 244.87.

References:

WO2012/178123,2012,A1 Location in patent:Page/Page column 64