A. Synthesis of 3-nitro-4-trifluoromethylbenzoic acid. A mixture of 3-nitro-4-trifluoromethylbenzoic acid (19.5 g, 83 mmol) with 10% Pd/C (4 g) in EtOAc (300 mL) was placed in a pressure vessel and oscillated under an H2 atmosphere at 40 psi. The vessel was repeatedly replenished with H2 until the pressure stabilized at 40 psi. after continuing to oscillate the reaction for 10 minutes, the reaction was terminated by bubbling N2 into the mixture for 30 minutes. The resulting black mixture was filtered through diatomaceous earth and washed with MeOH. The filtrate was concentrated to give 3-amino-4-trifluoromethylbenzoic acid (19.5 g, 98%) in white solid form, which did not require further purification.HPLC analysis: retention time (Rt) = 5.46 min. mass spectrometry (ESI): calculated value of C8H6F3NO2, 205.1; measured value of m/z, 204.3 [M-H]-. 1H NMR (CD3OD): δ 7.51 (s, 1H), 7.45 (d, J = 8.2 Hz, 1H), 7.30 (d, J = 8.0 Hz, 1H), 5.02 (br s, 3H).
