The invention relates to a process for preparing 1-substituted 5- and/or 3-hydroxypyrazoles of the formulae I and II
in 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 reacting
an alkyl 3-alkoxyacrylate of the formula III
in which R2, R3 independently of one another are C1-C6-alkyl or C3-C6-cycloalkyl with a hydrazine of the formula IV
in which R1 is as defined above
a) at a pH of 6-11 to give 5-hydroxypyrazoles of the formula I or
b) at a pH of 11-14 to give 3-hydroxypyrazoles of the formula II.
本发明涉及一种制备式I和式II的1-取代的5-和/或3-羟基
吡唑的方法,其中R1是C1-C6烷基,C2-C6烯基,C2-C6炔基,C3-C6环烷基或C1-C4烷氧基,这些基团可以被卤素,C1-C4烷氧基,苯氧基,C1-C6烷氧羰基,C1-C6烷基
硫酰羰基或具有3-14个环原子的环状环系统取代,包括将式III的烷基3-烷氧基
丙烯酸酯(其中R2,R3彼此独立地是C1-C6烷基或C3-C6环烷基)与式IV的
肼(其中R1如上所定义)反应:a)在pH值为6-11的条件下,得到式I的5-羟基
吡唑;b)在pH值为11-14的条件下,得到式II的3-羟基
吡唑。