2-(4-Ethynyl-2-fluoroanilino)-3,4-difluorobenzoic acid → 2-[(4-Ethyl-2-fluorophenyl)amino]-3,4-difluorobenzoic acid

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Reaction Steps

The product of Step C, 3,4-difluoro-2-[(4-ethynyl-2-fluorophenyl)amino]benzoic acid (300 mg, 1.03 mmol), was dissolved in absolute ethanol (30 mL) and 5% Pd/C (30 mg) added. This mixture was stirred under an atmosphere of hydrogen (60 psi) for 2 hours at room temperature. The Pd/C was removed over Celite®, which was washed well with additional ethanol, then the solvent removed from the resultant filtrate under reduced pressure to afford 2-[(4-ethyl-2-fluorophenyl)amino]-3,4-difluorobenzoic acid as an off-white solid (280 mg, 92%); m.p. (EtOAc/hexanes) 199-201° C. 1H NMR [400 MHz, (CD3)2SO] δ 14.10 (br s, 1 H), 9.31 (br s, 1 H), 7.80 (ddd, J=8.5, 6.1, 1.9 Hz, 1 H), 7.09 (dd, J=12.4, 1.5 Hz, 1 H), 7.04-6.92 (m, 3 H), 2.52 (q, J=7.6 Hz, 2 H), 1.17 (t, J=7.5 Hz, 3 H).

Provenance & Evidence