| 摘要 |
The invention relates to a process for preparing 1-substituted 5- and/or 3-hydroxypyrazoles of the formulae I and IIin which R1 is C1-C6-alkyl, C2-C6-alkenyl, C2-C6-alkynyl, C3-C6-cycloalkyl or C1-C4-alkoxy, where these groups may be substituted by halogen, C1-C4-alkoxy, phenoxy, C1-C6-alkoxycarbonyl, C1-C6-alkylthiocarbonyl or by a cyclic ring system having 3-14 ring atoms, which comprises reactingan alkyl 3-alkoxyacrylate of the formula IIIin which R2, R3 independently of one another are C1-C6-alkyl or C3-C6-cycloalkyl with a hydrazine of the formula IVin which R1 is as defined abovea) at a pH of 6-11 to give 5-hydroxypyrazoles of the formula I orb) at a pH of 11-14 to give 3-hydroxypyrazoles of the formula II. |
