5401-94-5

27996-87-8

5401-94-5

General procedure: hydrazine hydrate (NH2NH2-H2O, 3.0 mmol) was added dropwise to a stirred solution of 2-fluoro-5-nitrobenzaldehyde (1.0 mmol) in DMF (5 mL) at 23 °C. The reaction mixture was stirred continuously at the same temperature for 2 h. The progress of the reaction was monitored by thin-layer chromatography (TLC, unfolding agent: 20% ethyl acetate in hexane solution) to confirm the complete conversion of the starting material 2-fluoro-5-nitrobenzaldehyde. Upon completion of the reaction, the crude reaction mixture was poured into water and extracted with ethyl acetate (2 x 15 mL). The organic phases were combined, washed sequentially with water and saturated aqueous sodium chloride, dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure to give pure 5-nitroindazole.