Methods for the synthesis of the earlier unknown N-substituted 2-(5,6,7,8-tetrafluoro-4-oxo-1,4-dihydroquinolin-3-yl)glyoxylic acids and their esters from copper chelate of ethyl pentafluorobenzoylpyruvate were developed. The structure of intermediate ethyl 4-(R-amino)-2-oxo-3-pentafluorobenzoylbut-3-enoates is discussed.