6,7-Difluoro-1H-indazole

161793-17-5

1260384-41-5

The general procedure for the synthesis of 6,7-difluoro-1H-indazole from 2,3,4-trifluorobenzaldehyde was as follows: 2,3,4-trifluorobenzaldehyde (1.5 g, 9.4 mmol) was dissolved in 1,4-dioxane (6 mL) in a microwave reaction flask. Hydrazine (6 mL, 191 mmol) was then added. The reaction vial was sealed and heated at 150°C for 30 min under microwave radiation. Upon completion of the reaction, the reaction was quenched with water and extracted with ethyl acetate (EtOAc). The organic layer was washed with brine, dried over anhydrous magnesium sulfate (MgSO4) and concentrated. The residue was purified by silica gel column chromatography using 20% to 50% ethyl acetate/heptane as eluent to afford 664 mg (46% yield) of 6,7-difluoro-1H-indazole as a light brown powder.1H NMR (CDCl3, 300 MHz) data were as follows: δ (ppm) 8.10 (d, J = 3.4 Hz, 1H), 7.47 ( dd, J = 8.9, 4.0 Hz, 1H), 7.05 (ddd, J = 10.6, 8.9, 6.6 Hz, 1H).