Hydrazine → 5-bromo-4-methoxy-1H-indazole

Participants

Reaction Conditions

Reaction Steps

A solution of 3-bromo-6-fluoro-2-methoxybenzaldehyde (0.727 g, 3.12 mmol) and methoxylamine hydrochloride (0.260 g, 3.12 mmol) in 1,2-dimethoxyethane (4 mL) was treated with potassium carbonate (0.472 g, 3.42 mmol) and stirred at 20° C. for 5 h. The reaction mixture was filtered and the filtrate was concentrated in vacuo to give a residue. This residue was dissolved in 1,2-dimethoxyethane (4 mL), the resultant solution was treated with hydrazine (4 mL), warmed to 100° C. and stirred at that temperature for 15 h. The reaction mixture was diluted with ethyl acetate and water. Layers were separated and the organic layer was separated, washed with brine, dried with magnesium sulfate, filtered, and concentrated in vacuo to give a crude residue. This residue was triturated with ether to give the desired product (185 mg, 26%) as a gray solid. LCMS calculated for C8H8BrN2O (M+H)+: m/z=227.0, 229.0. found: 226.9, 229.0.

Provenance & Evidence