Hydrochloric Acid → 6-Bromopyridine-2,3-diamine

Participants

Reaction Steps

To a suspension of 2-amino-6-bromo-3-nitropyridine (21.8 g) in ethanol (220 ml)—water (22 ml) was added iron powder (39.0 g) at room temperature. Conc. hydrochloric acid (0.8 ml) was added and the mixture was gradually heated with stirring to start the reaction. The mixture was refluxed under heating for 2 hr, and an insoluble matter was removed by filtration while hot. The solvent was evaporated under reduced pressure, and water (200 ml) and active charcoal were added to the resulting solid, which was followed by heating. The insoluble matter was removed by filtration while hot, and water was evaporated under reduced pressure from the filtrate to give 2,3-diamino-6-bromopyridine (9.00 g) as a green brown powder. To the resulting solid from the above reaction were added ethanol (100 ml)—water (100 ml) and the mixture was heated for dissolution. The insoluble matter was removed by filtration. The solvent was evaporated under reduced pressure, and the residue was purified by silica gel column chromatography (hexane/ethyl acetate=1/3) to further give the objective compound (8.25 g) as a black-powder.

Provenance & Evidence