General procedure for the synthesis of 3-methylsulfonylaniline from 3-aminothioanisole: A mixture of Na2WO4 (0.067 g), 1 drop of acetic acid and H2O (5 mL) was added to a flask and heated to 65 °C. Subsequently, 3-methylthioaniline (500 mg, 3.59 mmol) was added and H2O2 (1.1 mL, 10.77 mmol) was added slowly and dropwise. The reaction mixture was stirred at 65 °C for 1.5 hours. After completion of the reaction, it was cooled to room temperature and extracted by adding 1N HCl (80 mL) and DCM (50 mL). The organic and aqueous phases were separated and the aqueous phase was then washed with DCM. The aqueous phase was alkalized with 25% NaOH solution and extracted with DCM. The organic phases were combined, washed with brine and dried over Na2SO4. The solvent was removed under reduced pressure to give the 3-methylsulfonylaniline derivative.Preparation of 3-(methylsulfonyl)aniline (158): Compound 158 was prepared from 3-methylsulfonylaniline (153) according to Method E. 557 mg of brown powder was obtained in 92% yield.1H NMR (500 MHz, CDCl3) δ 3.03 (s, 3H), 6.89 (ddd, J = 0.8, 2.3, 8.0 Hz, 1H), 7.21 (t, J = 2.1 Hz, 1H), 7.24 (dt, J = 1.1, 7.7 Hz, 1H), 7.30 (t, J = 7.8 Hz, 1H). 13C NMR (126 MHz, CDCl3) δ 44.40, 112.69, 116.37, 119.72, 130.30, 141.16, 141.16. 130.30, 141.16, 147.69. LC-MS (M+H+) calculated value C7H9NO2S 172, measured value 172.
