Patent ID: 6897322
Filing Date: 2005-05-24
Classification: C07D

Abstract:
1. A process for preparing 1-alkyl-3-aryl-5-difluoro- methoxy-1H-pyrazoles of the formula I in which Aryl is a mono- or polysubstituted phenyl ring and R which comprises reacting, in a first reaction step, a β-keto ester of the formula II, in which R a is C 1 -C 4 -alkyl and Aryl has the meanings given above with hydrazine, giving a hydroxypyrazole of the formula III which is reacted successively with chlorodifluoromethane and an alkylating agent R 1 -L in which R 1 has the meanings given above and L is a nucleophilically displaceable leaving group.