Regioselective cyclocondensation of ethyl 2-ethoxymethylidene-3-oxo-3-polyfluoroalkylpropionates with thiazolylhydrazines

Ethyl 2-ethoxymethylidene-3-oxo-3-polyfluoroalkylpropionates reacted in a regioselective fashion with thiazolylhydrazines to give the corresponding ethyl 1-thiazolyl-5-fluoroalkyl-1H-pyrazole-4-carboxylates. The product structure was determined on the basis of NMR and X-ray diffraction data.