1092394-16-5

The general procedure for the synthesis of 2-amino-[1,2,4]triazolo[1,5-a]pyridin-6-ol hydrobromide from 6-methoxy-[1,2,4]triazolo[1,5-a]pyridin-2-amine is as follows: cf. Examples 35-3; 6-methoxy-[1,2,4]triazolo[1,5-a]pyridin-2-amine (780 mg, 4.75 mmol) was mixed with 48% hydrobromic acid (3 mL) were mixed and the reaction was stirred under reflux conditions for 7 hours. Subsequently, 48% hydrobromic acid (2 mL) was added and the reaction continued to be stirred under reflux conditions for 3 hours. Upon completion of the reaction, the mixture was concentrated under reduced pressure and diisopropyl ether (2 mL) and ethanol (1 mL) were added to the residue. The precipitate was collected by filtration and washed with diisopropyl ether to afford 2-amino-[1,2,4]triazolo[1,5-a]pyridin-6-ol hydrobromide (984 mg, 89% yield) as a brown solid.1H-NMR (DMSO-d6, 300 MHz) δ 7.53-7.61 (2H, m), 8.34 (1H, dd, J = 1.8, 0.9 Hz), 10.57 (1H, br s).

[1] Patent: WO2008/150015, 2008, A1. Location in patent: Page/Page column 184-185
[2] Patent: WO2009/136663, 2009, A1. Location in patent: Page/Page column 162