| abstract |
A process for preparing alkyl 2-alkoxymethylene-4,4-difluoro-3-oxobutyrates (VI) n n n n n n n n n n where R is methyl or ethyl,n nfrom crude reaction mixtures of alkyl 4,4-difluoroacetoacetates (I)n n n n n n n n n n n byn a) reacting nn n n n n n n n n n n n where M is a sodium or potassium ion, and n n n n n n n n n n n n n n n n without additional solvent to form an enolate (V) n n n n n n n n n n n n n n b) releasing the corresponding alkyl 4,4-difluoroacetoacetate (I) from the enolate (V) by means of acid, n c) removing the salt formed from cation M and acid anion as a solid and n d) converting (I), without isolation from the crude reaction mixture, to the alkyl 2-alkoxymethylene-4,4-difluoro-3-oxobutyrate (VI),n nand the use of (VI) for preparing 1-methyl-3-difluoromethyl-pyrazol-3-ylcarboxyates VII |