[Synthesis]
Step 4: Synthesis of 2-bromo-5H-pyrrolo[2,3-b]pyrazin-7-amine
[00200] 2-Bromo-7-nitro-5H-pyrrolo[2,3-b]pyrazine (21.76 g, 89.54 mmol) was dissolved in a mixture of acetic acid (108.8 mL) and concentrated hydrochloric acid (108.8 mL), followed by addition of stannous dichloride (101.0 g, 447.7 mmol). The reaction mixture was stirred at room temperature for 1 hour. Upon completion of the reaction, the reaction was quenched by addition of 2 M NaOH solution and the aqueous layer was extracted with ethyl acetate (3 times). The organic layers were combined, dried with anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The resulting solid was washed with saturated sodium bicarbonate solution, the solid was collected, washed with water and dried to afford 2-bromo-5H-pyrrolo[2,3-b]pyrazin-7-amine (10.4 g, 54.6% yield).
1H NMR (400.0 MHz, DMSO-d6) δ: 11.50 (br s, 1H), 8.22 (s, 1H), 7.16 (s, 1H), 4.35 (br s, 2H) ppm; MS (ES+) m/z: 214.79. |