To a solution of N-Acetylglycine (406 mg, 3.47 mmol, 5.00 equiv) in pyridine (10 mL) was added triphenylphosphine (910 mg, 3.47 mmol, 5.00 equiv) at 0° C. After 5 min, carbon tetrabromide (1.15 g, 3.47 mmol, 5.0 equiv) was added, and the resulting yellow solution was maintained at 0° C. for 1.5 h. 5-(3-(Methylsulfonyl)phenyl)-[1,2,4]triazolo[1,5-a]pyridin-2-amine (0.200 g, 0.693 mmol, 1 equiv) was then added to the reaction mixture at 0° C. After 5 min, the reaction mixture was warmed to 24° C. and stirred overnight. Saturated aqueous sodium bicarbonate solution (20 mL), chloroform, and methanol were sequentially added to the reaction mixture. The solution was concentrated, and the resulting residue was purified by flash column chromatography (10% methanol, 1% ammonium hydroxide in dichloromethane) to afford product as white solid (220 mg, 78% yield). 1H NMR (400 MHz, CD3OD) δ 8.65 (s, 1H), 8.29 (dd, J=7.9, 1.1 Hz, 1H), 8.08 (dd, J=7.9, 1.0 Hz, 1H), 7.85-7.70 (m, 2H), 7.66 (dd, J=8.9, 1.2 Hz, 1H), 7.36 (dd, J=7.2, 1.2 Hz, 1H), 4.17 (s, 2H), 3.22 (s, 3H), 2.04 (s, 3H).
