24057-28-1

110-86-1

104-15-4

24057-28-1

(2) 4-methylbenzenesulfonic acid (5 g, 0.029 mol) and anhydrous tetrahydrofuran (40 mL) were added to the reactor under nitrogen protection and stirred at room temperature. The reaction mixture was cooled to 0-5 °C. At this temperature, a tetrahydrofuran solution of pyridine (2.75 g, 0.035 mol) was slowly added dropwise for 20 to 30 min, followed by continued stirring for 30 min. After completion of the reaction, the reaction mixture was filtered under nitrogen atmosphere and the solid product was collected. The filter cake was washed with anhydrous tetrahydrofuran (5 mL), and then the wet filter cake was placed in a vacuum oven and dried at 45-50 °C for 4 h to obtain the pyridinium salt of 4-methylbenzenesulfonate. The yield of the product was 6 g, the yield was 82.19% and the purity was 100% by HPLC.