公开(公告)号：CA2213853A1

公开(公告)日：1996-09-12

申请号：CA2213853

申请日：1996-02-27

Applicant: BASF AG

Inventor： FRETSCHNER ERICH ,  SCHR DER JUERGEN ,  MERKLE HANS RUPERT

IPC: C07D231/12 ,  C07D521/00

Abstract: A process is disclosed for preparing N-substituted pyrazoles having the general formula (I), in which R1 stands for C1 to C12 alkyl or C7 to C20 phenylalkyl, and R2, R3, R4 represent independently from each other hydrogen, C1 to C12 alkyl, C7 to C20 phenylalkyl or optionally substituted aryl residues, by reacting pyrazoles having the general formula (II), in which R2, R3 and R4 have above-said meanings, with an alcohol having the general formula (III) R1-O-H, in which R1 has above-said meanings, at temperatures from 50 to 400 ~C in the presence of a catalyst. The reaction of pyrazole (II) with compound (III) is carried out in a molar ratio from 0.001:1 to 1:1 in the liquid phase at a slight negative pressure up to an overpressure of 250 bars. Acids, their alkyl esters and/or their anhydrides are used as catalysts in a molar ratio from 0.0001:1 to 0.5:1 in relation to pyrazole (II).