Step 2: Synthesis of tert-butyl 3-aminobenzylcarbamate (3); To a solution of tert-butyl 3-nitrobenzylcarbamate (2, 0.69 g, 2.73 mmol) in ethanol (20 mL) was added 10% Pd-C (50 mg), and the resulting mixture was stirred for 30 min at room temperature under hydrogen atmosphere. The reaction progress was monitored by thin layer chromatography (TLC). After completion of the reaction, the reaction mixture was filtered through diatomaceous earth and washed with ethanol. Ethanol was evaporated from the filtrate under reduced pressure to give tert-butyl 3-aminobenzylcarbamate (3, 0.6 g, 98%). NMR hydrogen spectrum (400 MHz, CDCl3): δ 7.22 (s, 1H), 7.10-7.00 (t, 1H), 6.70-6.60 (d, 1H), 6.60-6.50 (m, 1H), 4.20 (bs, 2H), 1.40 (s, 9H).
