Synthesis
The suspension formed by 3-nitro-5-(trifluoromethyl)benzoic acid (103 g x 2 batches) obtained in step 1 and 10% palladium-carbon catalyst (5.15 g x 2 batches) in ethanol (1500 mL x 2 batches) was placed under the atmosphere of hydrogen at 1 atmospheric pressure, and the reaction was stirred for 7 hours at room temperature. After completion of the reaction, the catalyst was removed by filtration and the filtrate was concentrated under reduced pressure to afford the target product 3-amino-5-(trifluoromethyl)benzoic acid (180 g, 100% yield) as a light yellow powder. The product was characterized by 1H-NMR (300 MHz, CDCl3): δ 4.00-6.00 (2H, broad peak), 7.10 (1H, single peak), 7.53 (1H, single peak), 7.72 (1H, single peak).
References
[1] Patent: US2008/275085, 2008, A1. Location in patent: Page/Page column 45
[2] Chemistry - A European Journal, 2017, vol. 23, # 52, p. 12758 - 12762
[3] Patent: US2007/213371, 2007, A1. Location in patent: Page/Page column 70
[4] Journal of the American Chemical Society, 2017, vol. 139, # 43, p. 15308 - 15311
[5] Patent: WO2004/29038, 2004, A1. Location in patent: Page 44
