Hydrochloric Acid → 4-Amino-2,3-difluoro-5-nitrobenzoic acid

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Reaction Steps

Solid 5-nitro-2,3,4-trifluorobenzoic acid (0.75 g, 0.00339 mol) was dissolved in concentrated ammonium hydroxide (25 ml) to give instantly a yellow solution. A precipitate began to form within five minutes, after which time the mixture was acidified to pH 0 with concentrated aqueous hydrochloric acid. A yellow precipitate rapidly formed. The mixture was heated to boiling and was filtered hot. The yellow solids were washed with 10% aqueous hydrochloric acid and were suction dried to afford 0.47 g of a yellow powder; 64% yield; 1H-NMR (400 MHz; DMSO) δ13.32 (s, 1H), 8.36 (d, 1H, J=7.6 Hz), 7.98 (s, 2H); 19F-NMR (376 MHz; DMSO) δ−128.69 to −128.76 (m), −153.60 (d).

Provenance & Evidence