Synthesis
1,2,4-Triazole (9.28 g) was suspended in dichloromethane (110 mL) and dried by adding molecular sieves. Subsequently, triethylamine (13.6 g) was added to the suspension to completely dissolve 1,2,4-triazole. Under stirring, p-toluenesulfonyl chloride (25.62 g) was slowly added, taking about 1 hour. After addition, the reaction mixture was continued to be stirred for 30 minutes and then stirred overnight at room temperature. After completion of the reaction, the precipitated salt was removed by filtration. The filtrate was sequentially washed with water and dried with anhydrous sodium sulfate. After filtration to remove the desiccant, the filtrate was concentrated by rotary evaporator. Cyclohexane (300 mL) was added to the concentrated residue and left overnight to crystallize the product. The white crystals were collected by filtration, washed with cyclohexane (50 mL) and dried in an oven at 50 °C to give 1-(4-methylbenzenesulfonyl)-1,2,4-triazole 25.1 g in 83.7% yield, melting point 105-107 °C.
References
[1] Carbohydrate Research, 2003, vol. 338, # 5, p. 451 - 453
[2] Journal of Organic Chemistry, 2010, vol. 75, # 8, p. 2722 - 2725
[3] Patent: US2008/76933, 2008, A1. Location in patent: Page/Page column 3-5
[4] Patent: EP1258480, 2002, A1. Location in patent: Page 37
[5] Journal of Chemical Research, 2016, vol. 40, # 2, p. 101 - 106
