反应详情

46.8 g (0.2 mol) of 1-methyl-3,5-diphenylpyrazole together with 40 g (1.25 mol) of methanol are introduced into the reaction vessel. After 20.4 g (0.2 mol) of 96% strength sulfuric acid have been added, the reaction solution is brought to 160° C. by distilling off methanol. 640 g (20 mol) of methanol are metered in below the surface of the liquid in the course of 10 hours. After the reaction mixture has cooled, 73.5 g of a solidified melt are obtained. Recrystallization from 10 g of dichloromethane gives 67.7 g of 1,2-dimethyl-3,5-diphenylpyrazolium methylsulfate with a content of 99.4; (HPLC) of m.p. 158°-160° C., which corresponds to a yield of 93.4% of theory.

1. customis brought to 160° C.
2. distillationby distilling off methanol
3. customare metered in below the surface of the liquid in the course of 10 hours
4. temperatureAfter the reaction mixture has cooled
5. custom73.5 g of a solidified melt are obtained
6. customRecrystallization from 10 g of dichloromethane