| abstract |
A process for preparing 1-(het)aryl-3-hydroxypyrazoles of the formula I I where R is an unsubst. or subst. aromatic or heteroaromatic radical, n is 0, 1 or 2 and R' is a group which is stable under the reaction conditions, from propiolic acid esters of the formula II R'-CC-CO2R1 II where R1 is an alkyl, cycloalkyl or aryl group, and (het)arylhy-drazines of the formula III in a solvent in the presence of a base, which comprises first mixing II and III with one another in a solvent and then treating this mixture with the base at from 0°C to 60°C is described. |