Method of producing 1-alkyl-3-aryl-5-difluoromethoxy-1H-pyrazoles

US6897322B2 · kind B2 · utility

Assignee

• BASF SE

Inventors

• Thorsten Volk · Mannheim, DE
• Michael Puhl · Hirschberg, DE
• Cyrill Zagar · Ludwigshafen, DE
• Rene Lochtman · Mannheim, DE
• Norbert Gotz · Worms, DE
• Gerhard Hamprecht · Weinheim, DE

Key dates

• Filing date: Jan 15, 2002
• Grant date: May 24, 2005
• Expiry date: Jan 15, 2022

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D231/20
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The invention relates to a method of preparing 1-alkyl-3-aryl-5-difluoromethoxy-1H-pyrazoles of the formula (I), wherein aryl represents a mono- or polysubstituted phenyl ring, and R1 represents C1-C4 alkyl. The inventive method is characterized by reacting, in a first reaction step, a β-ketoester of the general formula (II) with hydrazine and by successively reacting the reaction product obtained with chlorodifluoromethane and a compound R1-L, wherein R1 has the meanings indicated above and L represents the leaving group of a nucleophilic displacement reaction.