Sulfuric Acid → 2-Amino-3,6-difluorobenzamide

Participants

Reaction Conditions

Reaction Steps

2-Amino-3,6-difluorobenzonitrile (2.3 g, 15 mmol) was added to concentrated sulfuric acid (5 mL) in a 25 mL 2-necked flask equipped with a thermometer with good stirring. The temperature rose to around 40° C. and the mixture became homogeneous. The solution was heated to 70° C. for 2 hours, cooled to room temperature, poured over ice, neutralized with concentrated NH4OH using water and NH4OH to rinse the flask and adding ice as necessary to keep the mixture cold. The separated solid was collected by filtration, washed with water and dried to give 2-amino-3,6-difluorobenzamide, 2.2 g. A second crop of 0.24 g was collected from the cold, concentrated filtrate, 95% overall. M.P. 121-123° C., LC/MS (ESI) m/z 172, 1H NMR (300 MHz, d6-DMSO) δ 7.70 (bs, 1H), 7.63 (bs, 1H), 7.10 (m, 1H), 6.32 (m, 1H), 6.05 (bs, 2H).

Provenance & Evidence