Ethyl Acetate → 5-Bromopyridine-2,3-diamine

Participants

Reaction Conditions

Reaction Steps

Commercially-available 5-bromo-3-nitro-pyridin-2-ylamine (20.0g, 92 mmol) was suspended in a 9:1 ethyl acetate:t-BuOH solution (470 ml). Tin chloride dihydrate (104 g, 460 mmol) was added, and the suspension was stirred under nitrogen for 2 h at 60° C. NaBH4 (1.75 g, 46 mmol) was added slowly, and the suspension was allowed to stir for another 3 hours. The reaction mixture was then cooled and filtered. The filtrate was extracted with 3 N HCl three times, and the collected acid washes were washed with ethyl acetate. The acidic solution was made basic by the careful addition of solid sodium carbonate. This aqueous solution was extracted with ethyl acetate three times, and the organic fractions were combined. The ethyl acetate solution was washed with brine, dried over MgSO4 and concentrated to yield the title product (6.5 g (38%), 35 mmol). 1H NMR (DMSO-d6): δ=11.99 (bs, 2H), 7.31 (d,1H, J=2.1 Hz), 6.84 (d, 1H, J=2.1 Hz), 5.90 (bs, 2H). Calculated mass=188.03, [M+H]+=189.

Provenance & Evidence