4-ethyl-2,3-dioxopiperazine-1-carbonyl chloride;1-chlorocarbonyl-4-ethyl-2,3-dioxopiperazine;2,3-Dioxo-4-ethylpiperazine-1-carbonyl chloride;1-Piperazinecarbonyl chloride, 4-ethyl-2,3-dioxo-;4-ethylpiperazin-2,3-dione-1-ylcarbonyl chloride;Cefoperazone Impurity 1;
