Preparation of 1-(het) aryl-3-hydroxypyrazoles

US5559244A · kind A · utility

Assignee

• BASF SE

Inventors

• Hartmann Konig · Heidelberg, DE
• Norbert Gotz · Worms, DE
• Reinhard Kirstgen · Neustadt, DE
• Bernd Muller · Flintbek, DE
• Klaus Oberdorf · Heidelberg, DE

Key dates

• Filing date: Apr 26, 1995
• Grant date: Sep 24, 1996
• Expiry date: Apr 26, 2015

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D231/22
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for preparing 1-(het)aryl-3-hydroxypyrazoles of the formula I ##STR1## where R is an unsubst. or subst. aromatic or heteroaromatic radical, PA1 n is 0, 1 or 2 and PA1 R' is a group which is stable under the reaction conditions, from propiolic acid esters of the formula II EQU R'--C.tbd.C--CO.sub.2 R.sup.1 II where R.sup.1 is an alkyl, cycloalkyl or aryl group, and (het)arylhydrazines of the formula III EQU R--NH--NH.sub.2 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.degree. C. to 60.degree. C. is described.