5-Aminoindazole

5401-94-5

19335-11-6

General procedure for the synthesis of 5-aminoindazole from 5-nitroindazole: To a 5000 mL autoclave equipped with a hydrogen inlet, thermometer, and mechanical stirrer, a tetrahydrofuran solution (THF, 3500 mL) of 5-nitro-1H-indazole (500 g, 3.06 mol) was added. Palladium-carbon catalyst (10%, 50 g, 141 mmol) was subsequently added. The reaction mixture was stirred overnight at 25 °C under hydrogen atmosphere (5 kg pressure). Upon completion of the reaction, the system was purged with nitrogen and the mixture was subsequently filtered. The filtrate was concentrated under vacuum to give 5-aminoindazole as a brown solid (420 g, 100% yield). Mass spectrometry (MS) data: m/z 134.1 ([M+H]+).