General procedure for the synthesis of N-methyl-2-fluoro-4-aminobenzamide from the compound (CAS: 956104-46-4): Trifluoroacetic acid (TFA, 1 mL) was slowly added dropwise to a solution of 4-methylamino-2-fluorobenzyl amide (60 mg, 0.21 mmol) in anhydrous dichloromethane (DCM, 0.5 mL), under protection of argon gas. The reaction mixture was stirred overnight at room temperature. Upon completion of the reaction, the solvent was removed by rotary evaporator and the residue was purified by silica gel fast column chromatography (eluent: hexane/ethyl acetate) to quantitatively obtain the target product, N-methyl-2-fluoro-4-aminobenzamide. The product structure was confirmed by 1H NMR (500 MHz, CDCl3) and 13C NMR (500 MHz, CDCl3): 1H NMR δ 2.98 (d, J = 4.8 Hz, 3H), 4.15 (br s, 2H), 6.32 (d, J = 14.3 Hz, 1H), 6.48 (d, J = 8.2 Hz, 1H), 6.61 ( br s, 1H), 7.90 (dd, J = 8.6 Hz, 1H); 13C NMR δ 26.63, 100.8 (d, J = 28.8 Hz), 110.3 (d, J = 244.6 Hz), 110.9, 133.3 (d, J = 4.3 Hz), 151.4 (d, J = 12.5 Hz), 162.2 (d, J = 244.6 Hz), 164.3 (d, J = 3.5 Hz).
