Hydrazine hydrate (1:1) → 5-Bromo-6-fluoro-3-methyl-1H-indazole

Participants

Reaction Conditions

Reaction Steps

To a solution of 1-(5-bromo-2,4-difluorophenyl)ethanone (4.9 g) in ethylene glycol (15 ml) was added hydrazine monohydrate (1.2 g) at room temperature, and the mixture was stirred at 160° C. for 26 hr. The reaction mixture was cooled to room temperature, and the insoluble material was removed. The filtrate was added to water, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated aqueous ammonium chloride solution, saturated aqueous sodium hydrogen carbonate solution and saturated brine, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (hexane/ethyl acetate) to give the title compound (3.2 g).

Provenance & Evidence