Process for the preparation of N-substituted pyrazoles

摘要

Process for the preparation of N-substituted pyrazoles of the formula I <IMAGE> in which R<1> is C1- to C12-alkyl or C7- to C20-phenylalkyl and R<2>, R<3> and R<4> independently of one another are hydrogen, C1- to C12-alkyl or C7- to C20-phenylalkyl by reaction of pyrazoles of the formula II <IMAGE> in which R<2>, R<3> and R<4> have the abovementioned meanings, with compounds of the formula III R<1> - O - R<5> in which R<1> has the abovementioned meanings and R<5> is hydrogen or R<1>, in the presence of a catalyst at temperatures from 200 to 550 DEG C and pressures from 0.001 to 50 bar by employing a heterogeneous catalyst as the catalyst.