Pyrazol-3-ylamine → 5-Bromopyrazolo[3,4-b]pyridine

Participants

Reaction Steps

1H-Pyrazol-5-amine (5.3 g, 64 mmol) and 2-bromomalonaldehyde (9.9 g, 64 mmol) were suspended in acetic acid (100 mL). The reaction mixture was heated to reflux under N2 for 6 hours. The reaction mixture was cooled to room temperature and concentrated to give a solid. The crude solids were suspended in MeOH (200 mL) and absorbed onto silica gel (200 g). The crude product was purified by column chromatography, eluting with hexanes/ethyl acetate (4:1), hexanes/ethyl acetate (2:1) to give 5-bromo-1H-pyrazolo[3,4-b]pyridine as a solid (3.1 g, 25%).

Provenance & Evidence