63547-22-8

63547-24-0

General procedure for the synthesis of 2-diphenylmethylsulfinylacetic acid from 2-[(diphenylmethyl)thio]acetic acid: 1. 2-[(Diphenylmethyl)thio]acetic acid (416 g, 1.61 mol) was suspended in purified water (4160 mL) at 25 to 30°C. 2. a 30% sodium hydroxide solution was prepared by dissolving 70.90 g (1.77 mol) of sodium hydroxide flakes/granules in 235 mL of purified water at 25 to 30 °C and added to the above suspension over 15 min. 3. 50% hydrogen peroxide (142.5 g, 2.095 mol) was slowly added over a period of 5 to 6 hours under stirring, maintaining the reaction temperature between 25 and 35 °C. 4. continue stirring the reaction mixture at 25 to 35 °C for 15 to 20 hours until the reaction is complete (the residual amount of feedstock should be less than 0.5% area). 5. Upon completion of the reaction, toluene (1664 mL) is added and the mixture is stirred for 10 minutes. 6. With stirring, the reaction mixture is acidified with concentrated hydrochloric acid (250 mL) while maintaining the temperature between 25 and 30°C. The reaction mixture is then purified by adding toluene (1664 mL). 7. the resulting substance was continued to be stirred at 25 to 30 °C for 1 hour. 8. The precipitated product was collected by filtration, washed sequentially with water (3 x 832 mL) and toluene (416 mL), and then dried to give 416 g of 2-[(diphenylmethyl)sulfinyl]acetic acid as a white crystalline powder (yield: 94.17%, HPLC purity: 99.3%).