5129-23-7

103440-95-5

5129-23-7

General procedure for the preparation of Example 39-2 3-amino-4-ethylbenzoic acid: 4-ethyl-3-nitrobenzoic acid (5.0 g, 27.4 mmol) was dissolved in methanol (50 ml) and 5% Pd-C catalyst (250 mg) was added. The reaction mixture was gradually warmed from 0 °C to room temperature and stirred for 1 h under hydrogen atmosphere. After completion of the reaction, the catalyst was removed by filtration and the filtrate was concentrated under reduced pressure. The resulting crystals were washed with mixed methyl tert-butyl ether/hexane solvent and dried to give 3-ethyl-4-aminobenzoic acid (3.2 g, 70.6% yield). The product was characterized by 1H-NMR (DMSO-d6, δ ppm): 12.40 (1H, brs), 7.21 (1H, d, J = 1.6Hz), 7.07 (1H, dd, J = 1.6 and 7.6Hz), 6.99 (1H, d, J = 7.7Hz), 5.06 (2H, brs), 2.45 (2H, quartet peak, J = 7.4 Hz), 1.11 (3H, t, J = 7.4 Hz).