4-(4-Hydroxy-7,8-dimethyl-2-oxo-1,2-dihydroquinolin-3-yl)-2,4-dioxobutyric acid isopentyl ester C??? ??, ??, ??

4-(4-Hydroxy-7,8-dimethyl-2-oxo-1,2-dihydroquinolin-3-yl)-2,4-dioxobutyric acid isopentyl ester ?? ?? ? ???

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4-(4-Hydroxy-7,8-dimethyl-2-oxo-1,2-dihydroquinolin-3-yl)-2,4-dioxobutyric acid isopentyl ester ?? ??