The general procedure for the synthesis of 2-(2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl)-1,2,4-triazolidine-3-thione from 2-(2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl)-1H-1,2,4-triazolidine-3(2H)-thione was carried out as follows: 2-(1-chlorocyclopropan-1-yl)-1-(2- chlorophenyl)-2-hydroxy-3-(1,2,4-triazolidine-5-thioxo-1-)propane IV (34.6 g, 0.10 mol) was dissolved in acetone (50 mL), followed by slow dropwise addition of hydrogen peroxide (0.15 mmol). The reaction mixture was stirred at 25°C for 2 hours. Upon completion of the reaction, sodium sulfite (6.5 g) was added to the reaction solution and stirring was continued for 1 h at room temperature and the end point of the reaction was detected using potassium iodide starch test paper. Water (50 mL) was added to the reaction system, followed by extraction with ethyl acetate (50 mL each time, three times). The organic phases were combined, dried with anhydrous sodium sulfate and concentrated under reduced pressure to give the crude product (35 g, 90% purity). The crude product was recrystallized from toluene to give prothioconazole (31.6 g) as a white solid in 98% yield and 90% purity.
![2-[2-(1-chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-1,2,4-triazolidine-3-thione](/CAS/20200401/GIF/222408-90-4.gif)
