Preparation of N-hydroxypyrazoles

US4945167A · kind A · utility

Assignee

• BASF SE

Inventors

• Ulf Baus · Dossenheim, DE
• Wolfgang Reuther · Neckargemünd, DE
• Erwin Hahn · Heidelberg, DE

Key dates

• Filing date: Jun 16, 1989
• Grant date: Jul 31, 1990
• Expiry date: Jun 16, 2009

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D249/08
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

N-hydroxypyrazoles of the general formula I ##STR1## where R.sup.1, R.sup.2 and R.sup.3 may be identical or different and are each hydrogen or halogen, are prepared by a process in which a pyrazole of the general formula II ##STR2## where R.sup.1, R.sup.2 and R.sup.3 have the meanings stated for formula I, is reacted with an aliphatic or aromatic peroxocarboxylic acid, preferably in the presence of from 0 to 15 moles of an alkali metal hydroxide, alkaline earth metal hydroxide, alkali meteal carbonate or alkaline earth metal carbonate in such a way that the reaction temperature is from -5.degree. C. to 60.degree.C. The reaction can be carried out in water as a solvent or in a 2-phase system consisting of water and an inert organic solvent which is poorly miscible with water, in the presence or absence of a suitable phase transfer catalyst. The peroxocarboxylic acid can be prepared in the reaction mixture before the reaction from H.sub.2 O.sub.2 and an acyl halide or a carboxylic anhydride or can be used in the form of an alkali metal salt or alkaline earth metal salt.