The general procedure for the synthesis of tert-butyl 2-aminobenzoate from tert-butyl 2-nitrobenzoate was as follows: tert-butyl 2-nitrobenzoate (194.8 g, 0.873 mol) was dissolved in ethanol (2.5 L) in a 5 L Parr reactor, and Raney's nickel catalyst (72 g), which had been washed five times with ethanol, was added. The reaction system was degassed three times (evacuated and then filled with nitrogen). Subsequently, the system was pressurized with hydrogen (initial pressure 30 psi) and the hydrogen pressure was increased to 50 psi after 1.5 h. The reaction mixture was stirred overnight, during which time the system pressure was reduced to 30 psi and then pressurized again to 50 psi. Upon completion of the reaction (about one day), the mixture was filtered through diatomaceous earth, and the filtrate was concentrated by evaporation to afford the brown oily product tert-butyl 2-aminobenzoate (160.8 g, 95% yield). The product was characterized by 1H NMR (300 MHz, CDCl3): δ 7.82 (dd, 1H), 7.22 (ddd, 1H), 6.55-6.65 (m, 2H), 5.7 (br s, 1H), 1.58 (s, 9H).
