Ammonium formate → 2-Bromo-5-chloroaniline

Participants

Reaction Conditions

Reaction Steps

1-Bromo-4-chloro-2-nitrobenzene (140 g, 0.59 mol) was dissolved in 2.5 L of MeOH with gentle heating (50° C.) in a hot water bath. A solution of ammonium formate (303 g, 4.81 mol) in 500 mL of water was added. Zinc powder (155 g, 2.36 mol) was added in small portions, resulting in heat evolution and refluxing of the solvent. Subsequent additions were made cautiously as to avoid build up of excess unreacted zinc. The reaction was cooled to room temperature and filtered through a large plug of CELITE® filter aid. The filtrate was then concentrated until a biphasic mixture of red oil and water was evident. The product was extracted with five 200 mL portions of diethyl ether. The organics were combined and dried over sodium sulfate, decanted, and concentrated in vacuo to a reddish-brown oil. The oil was redissolved in 150 mL of dichloromethane/hexanes and filtered through a plug of silica gel. The filtrate was concentrated to an orange oil. Addition of hexanes (200 mL) and cooling in a dry ice bath resulted in precipitation of 2-bromo-5-chloroaniline as a pale yellow solid (92.1 g, 75%) that was collected via vacuum filtration.

Provenance & Evidence