221615-72-1

221615-75-4

General procedure for the synthesis of 2-(4-methylsulfonylphenyl)-1-(6-methylpyridin-3-yl)-ethanone from 1-(6-methylpyridin-3-yl)-2-(4-(methylsulfanyl)phenyl)ethanone: 100 g of 1-(6-methylpyridin-3-yl)-2-[4-(methylsulfanyl)phenyl]ethanone (1.0 equiv.), 150 mL of ice-cold acetic acid (1.5 volume) and 30 mL of methanesulfonic acid (1.2 eq., 0.3 v/v; molecular weight 96.11 g/mol, density 1.481 g/mL) were added to a 3,000 mL three-necked flask fitted with a pyrometer, condenser, and dropping funnel. The reaction mixture was cooled to 5-10 °C. Under stirring, 120 mL of 30% w/w hydrogen peroxide solution (3 equiv, 1.20 v/v; molecular weight 34.02 g/mol, density 1.13 g/mL) was added slowly and dropwise at 5-10°C. The reaction mixture was warmed to 50 °C with stirring at 20-25 °C and kept reacting for at least 6 hours. Upon completion of the reaction, the mixture was cooled to 0-5 °C and a solution comprising 300 g of sodium thiosulfate (3 wt.) and water (10 v/v) was added in batches to a total volume of about 180-260 mL. The pH of the reaction mixture was adjusted with a 30% sodium hydroxide solution to 5.5-6.5. The mixture was continued to be stirred at 20-25 °C for 2 h. The suspension was then filtered. The solid product was washed with 2 x 400 mL of water and subsequently dried under vacuum at 40 °C for at least 12 hours. A final product of 105.7 g of the target product was obtained, which was analyzed by HPLC with a purity of 94% and a molar yield of 97.5% (area percentage).