Step 2: Preparation of 5-fluoro-1H-indazole
1-(5-Fluoro-1H-indazol-1-yl)ethan-1-one (2.1 g, 11.8 mmol) was dissolved in a mixture of methanol (20 mL) and concentrated hydrochloric acid (10 mL), heated to 50 °C and maintained for 2 hours. Upon completion of the reaction, the reaction mixture was evaporated to dryness under reduced pressure. The residue was alkalized with saturated sodium bicarbonate solution and extracted with ethyl acetate, the organic phase was washed with water and concentrated to afford the target product 5-fluoro-1H-indazole (1.6 g, 100% yield). The purity was analyzed by LCMS and was 95.9%; m/z = 137.2.
