5049-61-6

70-23-5

1286754-14-0

The general procedure for the synthesis of ethyl imidazo[1,2-a]pyrazine-3-carboxylate from pyrazin-2-amine (1 g, 10 mmol) and ethyl 3-bromo-2-oxopropanoate (2.30 g, 12 mmol) was as follows: pyrazin-2-amine was dissolved in 50 mL of ethylene glycol dimethyl ether, followed by the addition of 50 mL of methanol and ethyl 3-bromo-2-oxopropanoate. The reaction mixture was stirred at room temperature for 4 hours, then cooled to 0 °C and continued stirring for 30 minutes until the solid precipitated. The solid was separated by filtration and the filter cake was washed with ether (10 mL x 3). The resulting solid was dissolved in 50 mL of anhydrous ethanol and the solution was refluxed for 4 hours. After completion of the reaction, the reaction mixture was concentrated under reduced pressure, 100 mL of dichloromethane was added, and the organic layer was washed sequentially with saturated sodium carbonate solution (40 mL) and saturated sodium chloride solution (40 mL). The organic layer was dried with anhydrous sodium sulfate and filtered, and the filtrate was concentrated under reduced pressure to give ethyl imidazo[1,2-a]pyrazine-3-carboxylate (0.55 g, 28.9% yield) as a brown solid. Mass spectrometry analysis (ESI): m/z 192.1 [M+H]+.