To a 1 L round bottom flask equipped with a magnetic stir bar was suspended 3-(pyridin-4-yl)-1-trityl-1H-indazol-5-amine (13.00 g, 28.7 mmol) in 400.00 ml of water and cooled to 0° C. 80 ml of cone. H2SO4 was added slowly over a period of 15 min at 0° C. A solution of NaNO2(2.48 g, 35.9 mmol) in 15 ml of water was added to the mixture and allowed to stir at 0° C. for 30 min. A solution of NaN3 (3.36 g, 51.7 mmol) in water was then added dropwise over a period of 15 min. The mixture was slowly warmed to room temperature and stirred overnight. Upon completion, the precipitate was filtered, washed with water and dried to give 5-azido-3-(pyridin-4-yl)-1-trityl-1H-indazole (12.62 g) as a yellow solid.
