Yield: 60%

Reaction Conditions:

with N-Bromosuccinimide;potassium carbonate;potassium penicillin V in chloroform

Steps:

3 3-bromo[1,2,4]triazolo[4,3-a]pyridine
3-bromo[1,2,4]triazolo[4,3-a]pyridine
A mixture of [1,2,4]triazolo[4,3-a]pyridine (1.26 g) and NBS (1.98 g) with chloroform is refluxed for 5 h and then left for 14 h at room temperature.
A saturated aqueous solution of potassium carbonate (200 ml) and KOH (20 g) are added, the mixture is shaken and the organic layer is separated.
The aqueous layer is extracted with DCM twice.
The combined organic extract is dried over Na₂SO₄ and the solvent is evaporated in vacuum giving the desired product with 60% yield.

References:

Obshchestvo S Ogranichennoy Otvetstvennostyou "Fusion Pharma";CHILOV, Germes Grigorievich;TITOV, Ilya Yurievich EP2743266, 2014, A2 Location in patent:Page/Page column