Patent ID: 7002038

Claim:
A process for preparing 3-amino-4,4,4-trifluorocrotonic esters of formula (I) or the E/Z-isomers or tautomeric forms thereof wherein R 1 and R 2 are each independently hydrogen, an optionally substituted linear C 1 –C 4 -alkyl radical or an optionally substituted benzyl radical and R 3 is methyl or ethyl, comprising a) reacting an alkyl trifluoroacetate with an alkyl acetate of the formula CH 3 —CO—OR 3 and an alkali metal alkoxide to give an enolate of a trifluoroacetoacetic ester of formula (II) wherein M=Na or K and R 3 is as defined above, and subsequently b) reacting the alkali metal enolate of the trifluoroacetoacetic ester from stage a) without further purification directly with an amine of the formula NHR 1 R 2 , where R 1 and R 2 are each as defined above, in the presence of an acid to provide the 3-amino-4,4,4-trifluorocrotonic ester.