3-Amino-4-methoxybenzanilide is prepared by the reaction of 3-amino-4-methoxybenzoic acid and aniline. The steps are as follows:
A total of 0.17 mL (0.18 mmol) of DIC and 0.24 g (0.18 mmol) of HOBt were added to a dichloromethane solution of 0.20 g (0.12 mmol) of 1 at room temperature, and the reaction mixture was stirred for 0.5 h.
Then, 0.13 mL (0.14 mmol) of aniline was added to the mixture.
After approximately 3 h, 0.5 N NaOH was added to the solution.
The lower layer was isolated, and 0.5 N HCl was added until the aqueous solution was neutral.
The dichloromethane layer was washed three times with 10 mL of water, and then MgSO4 was added.
After 2 h, the solution was filtered, and the solvent was removed.
The residue was purified by column chromatography on silica gel (eluent: petroleum ether:ethyl acetate = 3:1) to yield the desired 3-Amino-4-methoxybenzanilide as a white solid (yield: 76%). Mp: 197-198 °C. 1H NMR (400 MHz, DMSO-d6) δ (ppm): 9.92 (1H, s, NH), 7.74 (2H, d, J = 9.0 Hz, PhH), 7.32 (2H, m, PhH), 7.21 (2H, d, J = 8.0 Hz, PhH), 7.06 (1H, m, PhH), 6.88 (1H, d, J = 8.0 Hz, PhH), 4.90 (2H, br s, NH2), 3.83 (3H, s, OCH3). ESI-MS (m/z): 243 (M + H)+.
