13185-09-6

2215-63-6

13185-09-6

4) Place 300g of 1-benzyl-3-hydroxy-1H-indazole (BZ-02) in a 3L three-necked flask, add 1200g of deionized water and start the magnetic stirrer. 357g of 30% sodium hydroxide aqueous solution was added slowly dropwise to form a suspended reaction system. The reaction system was placed in an oil bath, warmed to 80-85°C and maintained at this temperature until the reaction was complete and the solution became clarified. Subsequently, 25 g of activated carbon was added and stirring was continued for 30 minutes. The filtrate was filtered while hot, and the filtrate was slowly cooled to room temperature and then placed in an ice bath with stirring for 1 h. The filtrate was filtered again. The resulting filter cake was mixed with 600 mL of toluene and 600 mL of ethyl acetate and stirred for 10 minutes to obtain 326.0 g of off-white solid (BZ-03). 120 g of BZ-03 was taken and dehydrated with xylene at 140°C to collect 45 mL of water and 75 g of 1-benzyl-1H-indazole-3-hydroxy sodium salt. A total of 203.75 g of 1-benzyl-1H-indazole-3-hydroxy sodium salt was obtained by step 4), and the product was analyzed by high performance liquid chromatography (HPLC) with a purity of 97.94% and a yield of 62.4%.