| The new synthesis process of 2,3-dioxopiperazine and 4-ethyl-1-hydroxy-2,3-dioxop-iperazine was investigated in this paper. The products were analyzed by the methods, such as HPLC, IR,1H NMR, TLC, etc.(1) Synthesis and analysis of 2,3-dioxopiperazine2,3-dioxopiperazine was prepared by intermolecular condensation reaction that ethylenediamine reacted separately with diethyoxalate and cyclododecatrien. Effects of many factors such as the mole ratio of raw material, reaction temperature, reaction time, solvents and its dosage and feed way were considered. According to orthogonal experimentation the optimum reaction conditions were obtained. On the optimum conditions, the yield of 2,3-dioxopiperazine could respectively be 79.91% and 65.23% by using diethyoxalate and cyclododecatrien as raw material,respectively. With 2,3-dioxopiperazine prepared by oxamide and ethylenediamine in documents as reference substance ,2,3-dioxopiperazine synthesized in this experiment was analyzed qualitatively and quantitatively by melting point determination, IR Spetrum and 1H MNR Spectrum and HPLC. The results showed the purity of 2,3-dioxopiperazine had reached respectively 98.01% and 95.37% by diethyoxalate and cyclododecatrien as raw material.(2)Synthesis and analysis of 4-ethyl-1-hydroxy-2,3-dioxopiperazine4-ethyl-1-hydroxy-2,3-dioxopiperazine was prepared by using 4-et-hyl-2,3-dioxopiperazine and 30% H2O2 as main raw material. Effects of the mole ratio of raw material, reaction temperature and reaction time on the yield of the product were considered. Based on orthogonal experimentations the optimum reaction conditions were gained. Under the optimum reaction conditions, the yield of 4-ethyl-1-hydroxy-2,3-dioxopiperazine could reach 75.08%.In order to find out its propoties, 4-ethyl-1-hydroxy-2,3-dioxopiperazine was analyzed qualitatively and quantitatively by melting point determination, IR-Spectrum, 1H MNR Spectrum and HPLC. The results showed its purity had reached 98.92%.
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