Disclosed herein are methods for preparing [1,2,4]triazolo[4,3-a]pyridines, particularly (R)-6-(1-(8-fluoro-6-(1-methyl-1H-pyrazol-4-yl)-[1,2,4]triazolo[4,3-a]pyridin-3-yl)ethyl)-3-(2-methoxyethoxy)-1,6-naphthyridin-5(6H)-one, and precursors thereof, such as a method comprising reacting (R)—N-(3-fluoro-5-(1methyl-1H-pyrazol-4-yl) pyridin-2-yl)-2-(3-(2-methoxyethoxy)-5-oxo-1,6-naphthyridin-6(5H)yl) propanehydrazide (“HYDZ”): (HYDZ) under conditions sufficient to form (R)-6-(1-(8-fluoro-6-(1-methyl-IH-pyrazol-4-yl)-[1,2,4]triazolo[4,3-a]pyridin-3-yl)ethyl)-3-(2-methoxyethoxy)-1,6-naphthyridin-5(6H)-one (“A”): (A)