Synthesis
General procedure for the synthesis of 2-aminoterephthalic acid from 2-nitroterephthalic acid: in typical experiments, a mixture of nitroaromatic compounds (1.0 mmol), ammonium formate (3.3 mmol, 208 mg, 1.1 eq.), palladium catalyst (10% Pd/C, 2 mol%, 21 mg), and silicon dioxide (175 mg) was ball-milled in the presence of anhydrous methanol (η= 0.25 μL/mg) was ball-milled for 90 min in the presence of anhydrous methanol (η= 0.25 μL/mg). Upon completion of the milling, a small amount (~1 mg) of the crude reaction mixture was suspended in methanol and analyzed by thin-layer chromatography (TLC, usually using a solvent mixture of dichloromethane: methanol = 20:1 as eluent). The crude product was placed in a well-ventilated fume hood overnight, then suspended in methanol and filtered through a Büchner funnel. The filtrate is evaporated to give the target product 2-aminoterephthalic acid. If necessary, the final product can be further purified by column chromatography.
References
[1] Journal of Organic Chemistry, 1988, vol. 53, # 18, p. 4209 - 4218
[2] Molecules, 2018, vol. 23, # 12,
[3] Farmaco, Edizione Scientifica, 1984, vol. 39, # 11, p. 968 - 978
[4] Patent: CN103664684, 2016, B. Location in patent: Paragraph 0039
[5] Chemische Berichte, 1877, vol. 10, p. 145
