| 摘要 |
PCT No. PCT/EP96/03316 Sec. 371 Date Jan. 13, 1998 Sec. 102(e) Date Jan. 13, 1998 PCT Filed Jul. 26, 1996 PCT Pub. No. WO97/06148 PCT Pub. Date Feb. 20, 1997A process for the preparation of 1,2-dimethyl-3,5-diaryl-pyrazolium methylsulfates of the formula I <IMAGE> I where R1 and R2 independently of one another are hydrogen, C1-C4-alkyl, C3-C8-cycloalkyl, C1-C4-alkoxy, halogen, nitro, C1-C4-haloalkyl or aryl all of which are inert under the reaction conditions, in which 1-methyl-3,5-diarylpyrazoles of the formula II <IMAGE> II where R1 and R2 have the abovementioned meanings are reacted with a) methanol and SO3, b) methanol and sulfuric acid or optionally, c) methanol and methylsulfuric acid elevated temperatures.
|
