GENERAL STEPS: Methylimine ethyl ester hydrochloride (34.5 g, 0.315 mol) and 100 mL of formamide were added to a 250 mL three-necked flask at room temperature, followed by the addition of sodium ethoxide (21.4 g, 0.315 mol) and stirred for 10 min. Next, 2-hydrazino-2-oxoacetamide (10.8 g, 0.105 mol) was added, and the reaction mixture was heated to 130 °C for 10 h. The reaction pressure was maintained at 10 MPa. The progress of the reaction was monitored by liquid chromatography, and the reaction was stopped after confirming the complete conversion of 2-hydrazino-2-oxoacetamide. After the reaction mixture was cooled to room temperature, the precipitated solid was collected by filtration, washed with water and dried. The final 1,2,4-triazolecarboxamide white solid 9.2 g was obtained in 78.2% yield.
