Preparation of N-hydroxypyrazoles

US4945166A · kind A · utility

Assignee

• BASF SE

Inventors

• Ulf Baus · Dossenheim, DE
• Wolfgang Reuther · Neckargemünd, DE
• Rolf Fikentscher · Ludwigshafen, 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: C07D233/56
• 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, alkyl, halogen or aryl, or R.sup.1 and R.sup.2 or R.sup.2 and R.sup.3 together with the carbon atoms carrying these radicals form an aromatic or nonaromatic ring of 5 or 6 carbon atoms are prepared by a process in which PA0 (A) a pyrazole of the general formula II ##STR2## is converted in a conventional manner with an alkali metal hydroxide, alkali metal hydride or alkali metal carbonate into one of its metal salts of the general formula III ##STR3## where ME.sym. is a cation of an alkali metal, and (B) the resulting metal salt of the general formula III is reacted with dibenzoyl peroxide in an inert organic solvent or in a 2-phase system, in the presence or absence of a phase transfer catalyst.