Hydrazine → 5-Fluoro-3-Phenyl-1H-Indazole

Participants

Reaction Steps

A solution of 2,5-difluorobenzophenone (0.655 g, 3.0 mmol) and hydrazine (1.0 mL) in dried pyridine (10 mL) was heated at 130° C. for 5 hours and then concentrated and purified by chromatography (SiO2, 15–30% ethyl acetate/hexane) to provide the title compound (0.254 g, 40% yield): mp 124–125° C.; 1N NMR (CDCl3) δ 10.89 (br s, 1H), 7.94 (d, 2H), 7.65 (dd, 1H), 7.42–7.54 (m, 3H), 7.33 (dd, 1H), 7.21 (dt, 1H); EL-MS (m/z) 212 [M]+.

Provenance & Evidence