5-Chloro-2-nitrobenzoic acid → 3-Amino-5-chloro-2-nitrobenzoic acid

Participants

Reaction Steps

To a mixture of potassium tert-butoxide (38.9 g, 0.347 mol) and copper-(II) acetate monohydrate (0.9 g, 4.96 mmol) in DMF (160 ml) was added a solution of O-methylhydroxylamine hydrochloride (8.3 g, 99.3 mmol) and 3-chloro-6-nitrobenzoic acid (69; 10 g, 49.6 mmol) in DMF (160 ml) at 0° C. The resulting reaction mixture was stirred at that temperature for 3 h. It was then quenched with water, acidified with 10% HCl and extracted with EtOAc. The combined organic layers were dried (Na2SO4) and concentrated under reduced pressure. The residue was taken up in EtOAc and extracted with 10% aqueous NaOH. The combined aqueous layers were acidified with concentrated HCl to a pH=3 and then extracted with EtOAc. The combined organic layers were dried (Na2SO4) and concentrated under reduced pressure to afford 3-amino-5-chloro-2-nitrobenzoic acid 70 (6.5 g, 60.5%) as a brown red solid.

Provenance & Evidence