... 3,4-b]pyrazines from 4-aminopyridine, we decided to extend it to the synthesis of 2 ... b]pyrazines bearing a substituent in position 8. [6b-6e] Therefore, we decided to synthesize 8-bromo ... 2,3-Diamino-4-bromopyridine (19) was synthesized in two steps from 3-amino-2-nitropyridine ...