33422-35-4

107-15-3

141-05-9

33422-35-4

1. Ethylenediamine (1.17 mL, 17.42 mmol) and diethyl maleate (3 g, 17.42 mmol) were added to a 50 mL round bottom flask and dissolved in propanol (30 mL). 2. The reaction mixture was stirred at 55 °C for 16 h. 3. Upon completion of the reaction, the solvent was removed under reduced pressure by rotary evaporator. 4. The residue was placed in a vacuum drying chamber and The residue was dried to give the crude ethyl 2-(3-oxopiperazin-2-yl)acetate. 5. The crude product was used directly in the next step of the reaction without further purification. Yield: 3.4 g (quantitative yield).