Abstract: A novel and efficient 4-step synthesis of 2, 4-diamino-4-bromo-pyridine 4 in 56% overall yield by a double Curtius rearrangement as a key step is reported. N-amination of 2, 4-diamino-4-bromo-pyridine 4 with O-mesitylenesulfonylhydroxylamine 10 and subsequent reaction with aldehydes yielded, upon oxidative ringclosure, 5-bromo-triazolopyridines 2a– 2f. Thereafter, from a combinatorial parallel Suzuki cross-coupling reaction 260 previously ...
