2,5-Hexanedione → 5-Bromo-2-(2,5-dimethyl-1H-pyrrol-1-yl)pyridine

Participants

Reaction Steps

2,5-hexanedione (46.2 g, 0.41 mol) was added to a suspension of 2-amino-5-bromopyridine (50.0 g, 0.29 mol) and the reaction heated to reflux for 24 hours under Dean and Stark conditions. para-Toluene sulfonic acid (100 mg) was added and the reaction was refluxed for a further 18 hours. 8 ml of water were removed, so the reaction was cooled to room temperature, washed with water (100 ml) and passed through a plug of silica gel, eluting with toluene. The eluent was concentrated in vacuo and the residue dissolved in pentane:dichloromethane (1:1 by volume) and passed through a plug of silica gel, eluting with pentane:dichloromethane (1:1 by volume). The eluent was concentrated in vacuo to give a red liquid, which solidified on standing. The solid was recrystallised (isopropanol) to give the title compound as a pale yellow solid (54.4 g).

Provenance & Evidence